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 A305209 a(n) = [x^n] exp(Sum_{k>=1} (-1)^(k+1)*x^k/(k*(1 - n*x^k))). 1
 1, 1, 2, 12, 86, 885, 11234, 172711, 3112262, 64422126, 1506406702, 39279802969, 1130133725736, 35566642690293, 1215444767739120, 44823725114186355, 1774344335649148230, 75042087586212893216, 3377041177800135323864, 161125608740713509132809, 8124438293071792011560256 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS N. J. A. Sloane, Transforms FORMULA a(n) = [x^n] Product_{k>=1} (1 + x^k)^(n^(k-1)). MATHEMATICA Table[SeriesCoefficient[Exp[Sum[(-1)^(k + 1) x^k/(k (1 - n x^k)), {k, 1, n}]], {x, 0, n}], {n, 0, 20}] Table[SeriesCoefficient[Product[(1 + x^k)^(n^(k - 1)), {k, 1, n}], {x, 0, n}], {n, 0, 20}] CROSSREFS Cf. A098407, A292805, A305207. Sequence in context: A208977 A097237 A055531 * A290568 A181345 A193125 Adjacent sequences:  A305206 A305207 A305208 * A305210 A305211 A305212 KEYWORD nonn AUTHOR Ilya Gutkovskiy, May 27 2018 STATUS approved

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Last modified April 12 09:59 EDT 2021. Contains 342920 sequences. (Running on oeis4.)