cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-1 of 1 results.

A228970 Triangle of denominators of the coefficients t(n,k) in the formula B(2n) = -sum_{k=1..n-1} t(n,k)*B(2k)*B(2n-2k), where the B() are the even-indexed Bernoulli numbers.

Original entry on oeis.org

5, 7, 7, 85, 17, 85, 341, 341, 341, 341, 455, 91, 65, 91, 455, 5461, 5461, 5461, 5461, 5461, 5461, 4369, 4369, 21845, 257, 21845, 4369, 4369, 9709, 9709, 1387, 9709, 9709, 1387, 9709, 9709
Offset: 2

Views

Author

Jean-François Alcover, Sep 10 2013

Keywords

Comments

GCD of rows (5, 7, 17, 341, 13, 5461 ...) are Zsigmondy numbers A064080. - Paul Curtz, Sep 13 2013

Examples

			6/5;
5/7,        25/7;
28/85,     70/17,  588/85;
45/341, 1050/341, 4410/341, 3825/341;
...
		

References

  • George Boros and Victor H. Moll, Irresistible Integrals: Symbolics, Analysis and Experiments in the Evaluation of Integrals, Cambridge University Press (2006), p. 100.

Crossrefs

Cf. A228969 (numerators), A064080 (Zsigmondy numbers).

Programs

  • Mathematica
    Table[(2^(2*k) - 1)/(2^(2*n) - 1)* Binomial[2*n, 2*k], {n, 2, 9}, {k, 1, n-1}] // Flatten // Denominator
Showing 1-1 of 1 results.