This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A078669 #9 Aug 30 2024 14:54:26
%S A078669 1,0,0,0,0,1,0,1,4,0,0,1,2,2,2,1,2,4,3,1,5,3,2,11,5,1,2,7,8,15,8,5,11,
%T A078669 11,10,8,7,10,16,17,15,19,12,17,18,23,27,19,24,30,18,25,40,30,23,27,
%U A078669 29,31,33,48,48,50,30,49,51,51,58,55,67,52,59,50,52,63,78,67,92,107,94,74
%N A078669 Number of times n appears among the decimal digits of (n!)^n.
%e A078669 a(6)=1 because 6 appears one time in 6!^6 = 139314069504000000.
%o A078669 (PARI) {mcf(d, n)=my(c=0, m=10^#digits(d)); while(n>0, if(n%m==d, c++); n\=10; ); c }
%o A078669 a(n) = {mcf(n, (n!)^n)}
%Y A078669 Cf. A036740.
%K A078669 base,nonn
%O A078669 1,9
%A A078669 _Jason Earls_, Dec 16 2002