cp's OEIS Frontend

A129980 Sum of the digits of the sum of n!!, with n>=0.

%I A129980 #4 Aug 24 2012 10:49:59
%S A129980 1,2,4,7,6,3,15,12,18,9,15,24,24,33,24,33,24,33,24,51,42,51,33,51,69,
%T A129980 51,60,69,60,87,60,60,87,105,87,87,105,87,87,105,114,105,96,141,123,
%U A129980 123,159,150,159,150,141,141,132,168,159,150,177,159,159,168,195,186,195
%N A129980 Sum of the digits of the sum of n!!, with n>=0.
%e A129980 0!!=1
%e A129980 1!!=1 -> 1+1=2
%e A129980 2!!=2 -> 2+2=4
%e A129980 3!!=3 -> 4+3=7
%e A129980 4!!=8 -> 7+8=15 -> 1+5=6
%e A129980 5!!=15 -> 15+15=30 -> 3+0=3
%p A129980 P:=proc(n) local i,j,k,w,sf; sf:=1; for i from 0 by 1 to n do k:=i; w:=i-2; while w>0 do k:=k*w; w:=w-2; od; sf:=sf+k; w:=0; k:=sf; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; print(w); od; end: P(100);
%K A129980 easy,nonn,base
%O A129980 0,2
%A A129980 _Paolo P. Lava_ and _Giorgio Balzarotti_, Jun 14 2007