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 A173577 #8 Mar 21 2013 10:24:21 %S A173577 1,2,3,4,5,6,7,8,19 %N A173577 7-Factorions: equal to the sum of the 7-fold factorials of their digits in base 10. %e A173577 19 -> 1!!!!!!! + 9!!!!!!! = 1 + 9*2 = 1 + 18 = 19. %p A173577 P:=proc(n,m) local a,b,i,j,k,x,w; for i from 1 by 1 to n do a:=0; b:=0; w:=0; k:=i; while k>0 do w:=k-(trunc(k/10)*10); j:=w; x:=w-m; if w=0 then b:=1; else while x>0 do j:=j*x; x:=x-m; od; b:=j; fi; a:=a+b; k:=trunc(k/10); od; if a=i then lprint(i,a); fi; od; end: P(1000,7); %Y A173577 A014080, A097653, A173573-A173576 %K A173577 easy,fini,full,nonn,base %O A173577 1,2 %A A173577 _Paolo P. Lava_ and _Giorgio Balzarotti_, Feb 22 2010 %E A173577 Definition corrected by _Paolo P. Lava_, Feb 24 2010