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A131681
Phi(binomial(2*n,n)*n^2) (phi of A002736 = Apery numbers: n^2 C(2n,n). ).
0
0, 1, 8, 48, 384, 1440, 8640, 40320, 184320, 829440, 5529600, 18247680, 87588864, 474439680, 1532805120, 7664025600, 32699842560, 130288435200, 517321728000, 2184247296000, 9196830720000, 38626689024000, 188841590784000
OFFSET
0,3
MAPLE
with(numtheory):with(combinat):a:=n->phi(binomial(2*n, n)*n^2): seq(a(n), n=0..25);
CROSSREFS
Cf. A002736.
Sequence in context: A200161 A172111 A144014 * A077708 A165041 A165049
KEYWORD
nonn
AUTHOR
Zerinvary Lajos, Oct 07 2007
STATUS
approved