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A187745 Numerators of Bernoulli numbers B(2^n). 0
1, 1, 1, -1, -1, -3617, -7709321041217, -106783830147866529886385444979142647942017 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,6
COMMENTS
Interestingly, the terms |a(n)| mod 100 show some regularity : 1, 1, 1, 1, 1, 17, 17, 17, 17, 69, 69, 69, 69, 69, 69, 69, 69, 53, 53, 53, 53, 53, ...
The only prime term up to a(20) is a(5)
LINKS
FORMULA
a(n) = A164555(A131577(n))
MATHEMATICA
A164555[n_] := If[n <= 2, 1, BernoulliB[n] // Numerator]; A131577[n_] := If[n == 0, 0, 2^(n-1)]; a[n_] := A164555[A131577[n]];
(* or *) a[n_] := n!*Coefficient[ Series[x/(1-Exp[-x]), {x, 0, 2^6}], x, Max[1, 2^(n-1)]] // Numerator; Table[a[n], {n, 0, 7}]
PROG
(Magma)
A164555:=func<n | n le 2 select 1 else Numerator(Bernoulli(n))>;
[A164555(2^(n-1)): n in [0..10]]; // Bruno Berselli, Jan 09 2013
CROSSREFS
Sequence in context: A188309 A185495 A029829 * A329539 A329540 A223414
KEYWORD
sign,frac
AUTHOR
STATUS
approved

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Last modified June 19 13:19 EDT 2024. Contains 373503 sequences. (Running on oeis4.)