A047680 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..12.

Index entries for sequences related to Bernoulli numbers

MAPLE

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

PROG

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

CROSSREFS

Cf. A189995 (similar formula).

Sequence in context: A119162 A180067 A259365 * A090768 A119180 A088844

Adjacent sequences: A047677 A047678 A047679 * A047681 A047682 A047683

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

Edited by Andrey Zabolotskiy, Nov 30 2022

STATUS

approved