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%I #7 Jan 20 2024 18:49:43
%S 0,1,2,23,84,719,4976,40311,362780,3628799,39896064,479001599,
%T 6227020604,87178290975,1307674363904,20922789887999,355687427991024,
%U 6402373705727999,121645100408672000,2432902008176639559
%N a(n) = (n-1)!-n^tau(n)/n^2.
%C n and a(n) have the same parity.
%t Table[(n - 1)! - n^DivisorSigma[0, n]/n^2, {n, 2, 25}] (* _Wesley Ivan Hurt_, Jan 20 2024 *)
%Y Cf. A062758.
%K easy,nonn
%O 2,3
%A _Benoit Cloitre_, Apr 08 2002