A047680 a(n) = 2^(2*n-2) * (2^(2*n-1)-1) * numerator(|Bernoulli(4*n)|/n).

1, 28, 342736, 29398976, 22841912576, 495449389339648, 113828913905979392, 4138783908783021080576, 226044736813811127599528869888, 35882867158508587149623987273728, 5564179808875681941887049052192768, 197363311803624016534960016288517315362816

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Links

• Index entries for sequences related to Bernoulli numbers

Crossrefs

Cf. A189995 (similar formula).

Programs

Maple

(-1)*2^(2*n-2)*(2^(2*n-1)-1)*numer(bernoulli(4*n)/n);

PARI

a(n) = 2^(2*n-2) * (2^(2*n-1)-1) * numerator(abs(bernfrac(4*n))/n); \\ Michel Marcus, Nov 30 2022

Extensions

Edited by Andrey Zabolotskiy, Nov 30 2022