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Search: id:A109573
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A109573 E.g.f.: 2x/[1+exp(-2x)]. +0
1
0, 1, 2, 0, -8, 0, 96, 0, -2176, 0, 79360, 0, -4245504, 0, 313155584, 0, -30460116992, 0, 3777576173568, 0, -581777702256640, 0, 108932957168730112, 0, -24370173276164456448, 0, 6419958484945407574016, 0, -1967044844910430876860416, 0, 693575525634287935244206080, 0 (list; graph; listen)
OFFSET

0,3

COMMENT

"Bernoulli numbers" for 2x/[1+exp(-2x)].

MAPLE

G:=2*x/(1+exp(-2*x)): Gser:=series(G, x=0, 35): 0, seq(n!*coeff(Gser, x^n), n=1..32); # yields the signed sequence

MATHEMATICA

g[x_] = x/(-1 + Sum[(-2)^(n - 1)*x^n/n!, {n, 1, Infinity}]) h[x_, n_] = Dt[g[x], {x, n}] a[x_] = Table[h[x, n], {n, 0, 50}]; b = Abs[a[0]]

CROSSREFS

Sequence in context: A053205 A094030 A103424 this_sequence A021052 A099380 A020780

Adjacent sequences: A109570 A109571 A109572 this_sequence A109574 A109575 A109576

KEYWORD

sign

AUTHOR

Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Jun 27 2005

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Last modified July 23 17:35 EDT 2008. Contains 142285 sequences.


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