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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 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 June 21 16:12 EDT 2018. Contains 305624 sequences. (Running on oeis4.)