A179870 - OEIS

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A179870

a(n) = ((n-1)! * (n+1)!) ^ 2.

4, 36, 2304, 518400, 298598400, 365783040000, 842764124160000, 3344930808791040000, 21407557176262656000000, 209815467884550291456000000, 3021342737537524196966400000000, 61783437639904832303765913600000000

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..12.

FORMULA

a(n) = A175430(n) ^ 2 = ((Product_(k=1,2,...,n) k*A020725(k)) / n) ^ 2 = ((Product_(k=1,2,...,n) k*(k+1)) / n) ^ 2.

MATHEMATICA

Table[((n-1)!(n+1)!)^2, {n, 15}] (* Harvey P. Dale, Jul 12 2020 *)

PROG

(PARI) a(n)=(n-1)!^4*(n^4+2*n^3+n^2) \\ Charles R Greathouse IV, Jan 03 2013

CROSSREFS

Sequence in context: A174864 A374390 A175493 * A001152 A349848 A218515

Adjacent sequences: A179867 A179868 A179869 * A179871 A179872 A179873

KEYWORD

nonn,easy

AUTHOR

Jaroslav Krizek, Jul 30 2010

STATUS

approved