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%I #32 Oct 25 2021 22:20:07
%S 0,1,4,18,73,334,2592,18919,164476,1558521,1,187044031,2326111614,
%T 31214008090
%N Sum of digits of n^(n!).
%C a(10^k) = 1. - _Chai Wah Wu_, Dec 18 2019
%F a(n) = A007953(A053986(n)). - _Michel Marcus_, Aug 22 2013
%e a(3) = 18 because 3^3! = 729 with digit sum 7+2+9 = 18.
%p ds:= proc(n) local r;
%p `if`(n<10, n, ds(iquo(n, 10^iquo(length(n), 2), 'r'))+ds(r))
%p end:
%p a:= n-> ds(n^n!):
%p seq(a(n), n=0..10); # _Alois P. Heinz_, Dec 17 2011
%o (Python)
%o from math import factorial
%o def a(n): return sum(map(int, str(n**(factorial(n)))))
%o print([a(n) for n in range(10)]) # _Michael S. Branicky_, Jan 28 2021
%Y Cf. A053986, A007953, A202336.
%K nonn,base,more
%O 0,3
%A _Jacques ALARDET_, Dec 17 2011
%E a(11)-a(12) from _Lars Blomberg_, Jan 18 2013
%E a(13) from _Chai Wah Wu_, Oct 25 2021
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