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 A127554 #15 Jan 01 2025 14:41:35 %S A127554 0,1,2,4,1,7,10,19,19,19,19,28,37,37,55,55,37,46,46,73,73,64,82,100, %T A127554 100,118,109,100,127,127,145,118,163,145,154,172,172,154,181,181,199, %U A127554 172,226,208,253,226,262,262,253,271,235,271,262,280,325,325,307,343,334 %N A127554 Sum of the digits of left factorial !n. %H A127554 Seiichi Manyama, <a href="/A127554/b127554.txt">Table of n, a(n) for n = 0..10000</a> %F A127554 a(n) = A007953(A003422(n)). - _R. J. Mathar_, Apr 22 2007 %e A127554 !5 = 0!+1!+2!+3!+4! = 1+1+2+6+24 = 34 --> 3+4=7. %p A127554 P:=proc(n) local a,i,k,w; a:=0; for i from 1 by 1 to n do w:=0;k:=(i-1)!+a; a:=k; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; print(w); od; end: P(100); %t A127554 Array[Total[IntegerDigits[Total[Range[0,#-1]!]]]&,59,0] (* _James C. McMahon_, Jan 01 2025 *) %Y A127554 Cf. A003422, A004152, A007953. %K A127554 easy,nonn,base %O A127554 0,3 %A A127554 _Paolo P. Lava_ and _Giorgio Balzarotti_, Apr 17 2007