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 A166553 Triangle read by rows: expansion of p(x,t) = -exp(x*t)(2*(1 - 2*exp(t)) - 2*exp(t))/(1 + exp(t)), with coefficient of x^n scaled by multiplication by  (n!*(n + 2)!/4). 0
 1, 3, 3, 0, 24, 12, -30, 0, 180, 60, 0, -720, 0, 1440, 360, 2520, 0, -12600, 0, 12600, 2520, 0, 120960, 0, -201600, 0, 120960, 20160, -771120, 0, 3810240, 0, -3175200, 0, 1270080, 181440, 0, -61689600, 0, 101606400 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS I think the rows are indexed by t = 0, 1, 2, ..., and in each row we expand the polynomial in powers of x. - N. J. A. Sloane, Dec 14 2010 Row sums are 1, 6, 36, 210, 1080, 5040, 60480, 1315440, 5443200, -558835200, 718502400,... LINKS EXAMPLE {1}, {3, 3}, {0, 24, 12}, {-30, 0, 180, 60}, {0, -720, 0, 1440, 360}, {2520, 0, -12600, 0, 12600, 2520}, {0, 120960, 0, -201600, 0, 120960, 20160}, {-771120, 0,3810240, 0, -3175200, 0, 1270080, 181440}, {0, -61689600, 0, 101606400, 0, -50803200, 0, 14515200, 1814400}, MATHEMATICA p[t_] = -Exp[x*t](2*(1 - 2*Exp[t]) - 2*Exp[t])/(1 + Exp[t]); a = Table[ CoefficientList[(n!*(n + 2)!/4)*SeriesCoefficient[       Series[p[t], {t, 0, 30}], n], x], {n, 0, 10}]; Flatten[a] CROSSREFS Sequence in context: A247889 A309012 A137259 * A285863 A111843 A119537 Adjacent sequences:  A166550 A166551 A166552 * A166554 A166555 A166556 KEYWORD sign,tabl AUTHOR Roger L. Bagula, Dec 12 2010 EXTENSIONS I rewrote the definition. - N. J. A. Sloane, Dec 14 2010 STATUS approved

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Last modified August 9 02:14 EDT 2020. Contains 336310 sequences. (Running on oeis4.)