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A193472 Numerator of ez(n-1)*n!/(4^n-2^n) where ez(n) is the n-th coefficient of sec(t)+tan(t) for n>0, a(0) = 1. 2
1, 1, 1, 3, 1, 25, 1, 427, 1, 12465, 5, 555731, 691, 35135945, 7, 2990414715, 3617, 329655706465, 43867, 45692713833379, 174611, 1111113564712575, 854513, 1595024111042171723, 236364091, 387863354088927172625, 8553103, 110350957750914345093747, 23749461029 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

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, n-1)*n!/(4^n-2^n)):

A193472 := n -> numer(BG(n)): seq(A193472(n), n=0..28);

CROSSREFS

Cf. A000367, A002445, A009843, A193475, A193473.

Sequence in context: A138654 A175289 A072271 * A259208 A104033 A217472

Adjacent sequences:  A193469 A193470 A193471 * A193473 A193474 A193475

KEYWORD

nonn,frac

AUTHOR

Peter Luschny, Aug 07 2011

STATUS

approved

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Last modified August 20 20:33 EDT 2018. Contains 313927 sequences. (Running on oeis4.)