A047681 a(n) = 3^(2*n)*(3^(2*n)-1)*Bernoulli(2*n)/(2*n).

6, -54, 2106, -179334, 26414586, -5957217414, 1906398972666, -821369346492294, 458382160232420346, -321645776191296739974, 277173760840187306341626, -287758284647458145849816454, 354245505704926834826124160506, -510230879113388713374134585497734

Offset

1,1

References

J. W. Milnor and J. D. Stasheff, Characteristic Classes, Princeton, 1974, p. 283.

Links

Table of n, a(n) for n=1..14.

Index entries for sequences related to Bernoulli numbers.

Mathematica

Table[3^(2 n) (3^(2 n) - 1) BernoulliB[2 n] / (2 n), {n, 25}] (* Vincenzo Librandi, Apr 08 2020 *)

Prog

(PARI) a(n) = 3^(2*n)*(3^(2*n)-1)*bernfrac(2*n)/(2*n); \\ Michel Marcus, Mar 07 2020
(Magma) [3^(2*n)*(3^(2*n) - 1)*Bernoulli(2*n) / (2*n):n in [1..30]]; // Vincenzo Librandi, Apr 08 2020

Crossrefs

Sequence in context: A171681 A267837 A049037 * A075575 A073655 A119222

Adjacent sequences: A047678 A047679 A047680 * A047682 A047683 A047684

Keyword

sign

Author

N. J. A. Sloane

Status

approved