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 A052570 E.g.f.: x/(1-4*x). 1
 0, 1, 8, 96, 1536, 30720, 737280, 20643840, 660602880, 23781703680, 951268147200, 41855798476800, 2009078326886400, 104472072998092800, 5850436087893196800, 351026165273591808000, 22465674577509875712000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 513 FORMULA Recurrence: {a(1)=1, a(0)=0, (-4-4*n)*a(n)+a(n+1)=0.} 4^(n-1)*n! for n >= 1. MAPLE spec := [S, {S=Prod(Z, Sequence(Union(Z, Z, Z, Z)))}, labeled]: seq(combstruct[count](spec, size=n), n=0..20); MATHEMATICA With[{nn=20}, CoefficientList[Series[x/(1-4x), {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jan 15 2017 *) CROSSREFS A034177 is an essentially identical sequence. - Philippe Deléham, Sep 18 2008 Sequence in context: A098430 A220285 A034177 * A002168 A114425 A224767 Adjacent sequences:  A052567 A052568 A052569 * A052571 A052572 A052573 KEYWORD easy,nonn AUTHOR encyclopedia(AT)pommard.inria.fr, Jan 25 2000 STATUS approved

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Last modified October 15 00:14 EDT 2019. Contains 328025 sequences. (Running on oeis4.)