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 A171721 Coefficient expansion of: f(t,y)=((1 + y)/y - Exp[t/2])/(-1 + y*Exp[t]) 0
 1, 1, 3, 2, 3, 7, 17, 17, 7, 15, 116, 122, 116, 15, 31, 627, 1262, 1262, 627, 31, 63, 2990, 12433, 15108, 12433, 2990, 63, 127, 13309, 107151, 201973, 201973, 107151, 13309, 127, 255, 56936, 830628, 2612184, 3321914, 2612184, 830628, 56936, 255, 511 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Row sums are: 2, 8, 48, 384, 3840, 46080, 645120, 10321920, 185794560, 3715891200,... LINKS FORMULA f(t,y)=((1 + y)/y - Exp[t/2])/(-1 + y*Exp[t]) EXAMPLE {1, 1}, {3, 2, 3}, {7, 17, 17, 7}, {15, 116, 122, 116, 15}, {31, 627, 1262, 1262, 627, 31}, {63, 2990, 12433, 15108, 12433, 2990, 63}, {127, 13309, 107151, 201973, 201973, 107151, 13309, 127}, {255, 56936, 830628, 2612184, 3321914, 2612184, 830628, 56936, 255}, {511, 237863, 5979980, 30947132, 55731794, 55731794, 30947132, 5979980, 237863, 511}, {1023, 979298, 40909331, 336803864, 900995822, 1156512524, 900995822, 336803864, 40909331, 979298, 1023} MATHEMATICA f[t_, y_] = ((1 + y)/y - Exp[t/2])/(-1 + y*Exp[t]); a = Table[ CoefficientList[FullSimplify[ExpandAll[(-1 + y)^(n + 1)*(-2)^n*n!*SeriesCoefficient[ Series[f[t, y], {t, 0, 30}], n]]], y], {n, 1, 10}] Flatten[a] CROSSREFS Sequence in context: A323895 A274508 A227104 * A225695 A226469 A073341 Adjacent sequences:  A171718 A171719 A171720 * A171722 A171723 A171724 KEYWORD nonn,uned AUTHOR Roger L. Bagula, Dec 16 2009 STATUS approved

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Last modified January 28 10:02 EST 2020. Contains 331319 sequences. (Running on oeis4.)