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A131092
Coefficient of y^(n-2) in expansion of (y+n!)^n.
1
4, 108, 3456, 144000, 7776000, 533433600, 45519667200, 4740548198400, 592568524800000, 87634300723200000, 15143207164968960000, 3024511467403345920000, 691604955546231767040000, 179551286536040939520000000, 52531576403687406305280000000
OFFSET
2,1
LINKS
FORMULA
a(n) = n*(n-1)*(n!)^2/2. - Matthew House, Feb 15 2017
MATHEMATICA
a = {}; Do[k = CoefficientList[Expand[(y + n!)^n], y]; AppendTo[a, k[[Length[k] - 2]]], {n, 1, 50}]; a
Table[n(n-1) (n!)^2/2, {n, 2, 20}] (* Harvey P. Dale, Sep 03 2022 *)
CROSSREFS
Cf. A001563.
Sequence in context: A302113 A357510 A336028 * A360092 A123056 A024263
KEYWORD
nonn
AUTHOR
Artur Jasinski, Oct 22 2007
STATUS
approved