A255505 Numerator of Bernoulli(2n)/(2n!).

1, 1, -1, 1, -1, 1, -691, 1, -3617, 43867, -174611, 77683, -236364091, 657931, -3392780147, 1723168255201, -7709321041217, 151628697551, -26315271553053477373, 154210205991661, -261082718496449122051, 1520097643918070802691

Offset: 0

Author

Jean-François Alcover, Feb 24 2015

Keywords

• sign
• frac

Comments

This sequence is different from A001067 or A046968 or A141590, at least at a(52).

Examples

			The sequence Bernoulli(2n)/(2n!) (n >= 0) begins 1/2, 1/12, -1/120, 1/504, -1/1440, 1/3168, -691/3931200, 1/8640, -3617/41126400, ...
		

Links

• MathOverflow, What can be said about a function given its asymptotic expansion?

Crossrefs

Cf. A000367, A001067, A046968, A141590, A255506 (denominator).

Programs

Magma

[Numerator(Bernoulli(2*n)/(2*Factorial(n))):n in [0..30]]; // Vincenzo Librandi, Feb 24 2015

Mathematica

Table[Numerator[BernoulliB[2 n]/(2 n!)], {n, 0, 25}]

PARI

a(n) = numerator(bernfrac(2*n)/(2*n!)); \\ Michel Marcus, Feb 24 2015

Sage

[numerator(bernoulli(2*n)/(2*factorial(n))) for n in (0..25)] # Bruno Berselli, Feb 24 2015