News 
11Aug2008

Program Calcbn 2.0 for Windows/Linux, 32/64bit, single & multithreaded 
10Feb2003

The two millionth Bernoulli number computed by program Calcbn 1.2 
8Feb2003

The 1.5 millionth Bernoulli number computed by program Calcbn 1.2 
6Feb2003

Program Calcbn 1.2: now up to 1.7 times faster 
26Jan2003

Program Calcbn 1.1: now 1.6 times faster by optimization of implementation 
18Jan2003

Program Calcbn 1.0 for Windows/Linux and some factorizations of numerators 
16Dec2002

The one millionth Bernoulli number was computed by program Calcbn 1.0 
15Dec2002

Website created 
Introduction 
The Bernoulli numbers B_{n}_{ }play an important role in several topics of mathematics. These numbers can be defined by the power series
where all numbers B_{n} are zero with odd index n > 1. The evenindexed rational numbers B_{n} alternate in sign. The first values are
Sum of consecutive integer powers 
Jakob Bernoulli introduced a sequence of rational numbers, later called Bernoulli numbers, to compute the sum of consecutive integer powers. This formula is given by
Values of the Riemann zeta function 
The Bernoulli numbers are connected with the Riemann zeta function
on the positive real axis by Euler's formula for positive even n, also valid for n = 0:
The functional equation of ζ(s) leads to the following formula for negative integer arguments:
Structure of the denominator 
The structure of the denominator of B_{n} for positive even n is given by the Clausen  von Staudt Theorem:
Structure of the numerator 
The numerator of B_{n}/n for positive even n equals 1 only for n = 2,4,6,8,10,14; otherwise this numerator is a product of powers of irregular primes. Since B_{n}/n is a pinteger for primes p where p1 does not divide n, the structure of the numerator of B_{n}_{ }is given by
The first product is a trivial factor of B_{n} which divides n. The second product consists only of powers of irregular primes p_{v} which are not easy to determine for larger n.
Kummer congruences 
The Kummer congruences describe the most important arithmetical properties of the Bernoulli numbers which give a modular relation between these numbers.
The two millionth Bernoulli number 
More than 10 million digits were omitted in the middle of the numerator!
The 1.5 millionth Bernoulli number 
More than 7.4 million digits were omitted in the middle of the numerator!
The one millionth Bernoulli number 
More than 4.7 million digits were omitted in the middle of the numerator!
Program Calcbn  A multithreaded program for computing Bernoulli numbers via Riemann zeta function 
Version 
Windows (32bit) / Exe
single & multithreaded 
Linux (64bit) / Source
single & multithreaded 
2.0

calcbn32exe.zip (150 KB)

calcbn64src.zip (26 KB) 
Timings on an Intel Core2Duo E6850 @ 3 GHz, computation of the 100000th Bernoulli number: Windows XP (32bit): 16.8s (one thread), 8.7s (two threads). Linux openSUSE 11.0 (64bit): 11.3s (one thread), 5.7s (two threads).
Factorization of numerators 
Factorization of numerators of Bernoulli numbers with index 2 to 10000. Computed prime factors are less than one million: factors10t.txt (111 KB).
Irregular pairs of higher order 
The irregular pairs of higher order describe the first appearance of higher powers of irregular prime factors of B_{n}/n. An irregular pair (p,n) of order r has the property that p^{r} divides B_{n}/n with n < (p1)p^{r1}. Note that n is always an even positive integer. For r = 1 this gives the usual definition of irregular pairs; note that the condition p divides B_{n}/n is then equal to p divides B_{n}. There exists a criterion to check whether the sequence of irregular pairs of higher order is unique. It has been proven for all irregular primes below 12 million that there are only unique sequences. Writing sequences padically these pairs of higher order provide an approximation of a uniquely existing zero of the padic zeta function associated with an irregular pair. For definition and properties see [R3]. Example:
A conjectural structural formula for the Bernoulli numbers 
Assuming that all sequences of irregular pairs of higher order are unique, resp. each padic zeta function associated with an irregular pair (p,l) has a unique simple zero χ _{(p,l)}, one can describe the structure of divided Bernoulli numbers, resp. the value of the Riemann zeta function at negative odd integer arguments, as follows:
Under the proposed assumption, one can give some interpretation of the formula above. The denominator can be described by poles (always lying at 0) and the numerator by zeros of padic zeta functions measuring the distance to them using the padic metric induced by the standard ultrametric absolute value  _{p}. Note that this formula is valid for all irregular primes below 12 million. For detailed statements see [R3]. Equivalently, the formula conjecturally states for the Bernoulli numbers that
If there should exist a sequence of irregular pairs of higher order that is not unique, – the socalled singular case –, then the formulas given above remain valid. An additional product has to be added for those irregular pairs which belong to the singular case. This product can be described by trees of irregular pairs of higher order, which is much more complicated. Since there is not known any example of the singular case, the conjectural formulas are presented here in a simple form.
A conjectural structural formula for the Euler numbers 
Similarly, for the Euler numbers E_{n}, n > 0 and even, one can state also a conjectural formula:
Here (p,l) are irregular pairs associated with the Euler numbers and the ξ _{(p,l)}_{ }are certain zeros of padic Lfunctions.
Connections with class numbers of imaginary quadratic fields 
Let h(d) denote the class number of the imaginary quadratic field Q(√d) of discriminant d < 4. For primes p > 3 one has the connections with Bernoulli and Euler numbers due to Carlitz [R1]:
Since h(p) < p and h(4p) < p for these cases, this shows that p cannot divide special Bernoulli and Euler numbers. That means for Bernoulli numbers that an irregular pair (p,(p+1)/2) for p ≡ 3 (mod 4) cannot exist.
Asymptotic formula 
The product of Bernoulli numbers is described by the following asymptotic formula, see [R4],
with an asymptotic constant C_{2} = 4.855096646522... which is given by
where C_{1} = 1.8210174514992... is the product over all values of the Riemann zeta function at even positive integers and A = 1.2824271291... is the GlaisherKinkelin constant:
Links & References 