cp's OEIS Frontend

A117469 The largest part summed over all partitions of n in which every integer from the smallest part to the largest part occurs.

%I A117469 #3 Mar 30 2012 17:36:09
%S A117469 1,3,6,9,13,19,24,30,42,49,61,79,92,110,144,162,195,242,278,332,405,
%T A117469 463,546,656,759,882,1049,1205,1399,1655,1887,2181,2546,2909,3361,
%U A117469 3880,4422,5069,5831,6641,7566,8666,9818,11159,12730,14376,16281,18465,20828
%N A117469 The largest part summed over all partitions of n in which every integer from the smallest part to the largest part occurs.
%C A117469 a(n)=Sum(k*A117468(n,k),k=1..n).
%F A117469 G.f.=sum(x^j*product(1+x^i, i=1..j-1)*[1+(1-x^j)sum(x^i/(1+x^i), i=1..j-1)]/(1-x^j)^2, j=1..infinity) (obtained by taking the derivative with respect to t of the g.f. G(t,x) of A117468 and setting t=1).
%e A117469 a(5)=13 because in the 5 (=A034296(5)) partitions in which every integer from the smallest to the largest part occurs, namely [5],[3,2],[2,2,1],[2,1,1,1] and [1,1,1,1,1], the sum of the largest parts is 5+3+2+2+1=13.
%p A117469 g:=sum(x^j*product(1+x^i,i=1..j-1)*(1+(1-x^j)*sum(x^i/(1+x^i),i=1..j-1))/(1-x^j)^2,j=1..70): gser:=series(g,x=0,60): seq(coeff(gser,x,n),n=1..55);
%Y A117469 Cf. A117466, A117467, A117468.
%K A117469 nonn
%O A117469 1,2
%A A117469 _Emeric Deutsch_, Mar 19 2006