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A000386
Coefficients of ménage hit polynomials.
(Formerly M4137 N1715)
1
0, 0, 0, 1, 6, 20, 134, 915, 7324, 65784, 657180, 7223637, 86637650, 1125842556, 15757002706, 236298742375, 3780061394232, 64251145312880, 1156374220457784, 21968796934412649, 439337048505773790, 9225384943965382564, 202945418255342821470
OFFSET
0,5
REFERENCES
J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 198.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
MATHEMATICA
max = 22; f[x_, y_] := Sum[n!*((x*y)^n/(1+x*(y-1))^(2*n+1)), {n, 0, max}]; t = MapIndexed[Take[#1, #2[[1]]]&, CoefficientList[Series[f[x, y], {x, 0, max}, {y, 0, max}], {x, y}]]; a[n_] := If[n<3, 0, t[[n+1, n-2]]]; Table[ a[n], {n, 0, max}] (* Jean-François Alcover, Feb 08 2016, after Vladeta Jovovic in A058057 *)
CROSSREFS
A diagonal of A058057.
Sequence in context: A074013 A333896 A114959 * A000387 A145221 A332391
KEYWORD
nonn
STATUS
approved