

A193473


Denominator of ez(n1)*n!/(4^n2^n) where ez(n) is the nth coefficient of sec(t)+tan(t) for n>0, a(0) = 1.


2



1, 2, 6, 56, 30, 992, 42, 16256, 30, 261632, 66, 4192256, 2730, 67100672, 6, 1073709056, 510, 17179738112, 798, 274877382656, 330, 628292059136, 138, 70368735789056, 2730, 1125899873288192, 6, 18014398375264256, 870
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OFFSET

0,2


LINKS

Table of n, a(n) for n=0..28.
Peter Luschny, The lost Bernoulli numbers.


MAPLE

gf := (f, n) > coeff(series(f(x), x, n+1), x, n):
BG := n >`if`(n=0, 1, gf(sec+tan, n1)*n!/(4^n2^n)):
A193473 := n > denom(BG(n)): seq(A193473(n), n=0..28);


CROSSREFS

Cf. A000367, A002445, A009843, A193475, A193472.
Sequence in context: A153450 A179389 A084123 * A181509 A213026 A074023
Adjacent sequences: A193470 A193471 A193472 * A193474 A193475 A193476


KEYWORD

nonn,frac


AUTHOR

Peter Luschny, Aug 07 2011


STATUS

approved



