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%I #12 Nov 13 2022 07:13:46
%S 1,4,12,52,240,1464,10080,80736,725796,7258080,79833600,958006368,
%T 12454041600,174356602560,2615348737440,41845579937856,
%U 711374856192000,12804747412916160,243290200817664000,4865804016367800960,102181884343418940480,2248001455555375027200
%N Dirichlet convolution of factorials with themselves.
%H Seiichi Manyama, <a href="/A034716/b034716.txt">Table of n, a(n) for n = 1..449</a>
%F a(n) ~ 2 * n!. - _Vaclav Kotesovec_, Jan 28 2019
%t Table[Sum[d!*(n/d)!, {d, Divisors[n]}], {n, 1, 25}] (* _Vaclav Kotesovec_, Jan 28 2019 *)
%o (PARI) a(n)=sumdiv(n,d, (d!) * (n/d)! ); /* _Joerg Arndt_, Oct 07 2012 */
%K nonn
%O 1,2
%A _Erich Friedman_
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