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A181859 a(n) = gcd(n^2, n!) / gcd(n^2, n!/floor(n/2)!^2). 1
1, 1, 1, 1, 4, 1, 9, 1, 32, 9, 25, 1, 12, 1, 49, 5, 128, 1, 81, 1, 100, 21, 121, 1, 144, 25, 169, 27, 98, 1, 5, 1, 512, 11, 289, 7, 108, 1, 361, 13, 80, 1, 147, 1, 242, 3, 529, 1, 64, 49, 625, 17, 338, 1, 729, 55, 56, 57 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..57.

FORMULA

a(n) = A170826(n) / A181861(n).

MAPLE

A181859 := n -> igcd(n^2, n!)/igcd(n^2, n!/iquo(n, 2)!^2);

MATHEMATICA

a[n_] := GCD[n^2, n!]/GCD[n^2, n!/Quotient[n, 2]!^2];

Table[a[n], {n, 0, 57}] (* Jean-Fran├žois Alcover, Jun 18 2019 *)

PROG

(PARI) a(n)=if(isprime(n), n, if(n==4, 8, n^2))/gcd(n^2, n!/(n\2)!^2) \\ Charles R Greathouse IV, Feb 01 2013

CROSSREFS

Cf. A170826, A181860, A056040, A000290.

Sequence in context: A326582 A276171 A306603 * A218972 A331151 A085383

Adjacent sequences:  A181856 A181857 A181858 * A181860 A181861 A181862

KEYWORD

nonn

AUTHOR

Peter Luschny, Nov 21 2010

STATUS

approved

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Last modified April 5 21:08 EDT 2020. Contains 333260 sequences. (Running on oeis4.)