%I A051747
%S A051747 2,10,31,76,161,308,546,912,1452,2222,3289,4732,6643,9128,12308,16320,
%T A051747 21318,27474,34979,44044,54901,67804,83030,100880,121680,145782,173565,
%U A051747 205436,241831,283216,330088,382976,442442,509082,583527,666444,758537
%N A051747 a(n)=(1/120)*n*(n+1)*(n+2)*(n^2+7*n+32).
%F A051747 a(n)=binomial(n+4, n-1)+binomial(n+2, n-1)
%F A051747 Convolution of triangular numbers with triangular numbers + 1, i.e. [1, 
               3, 6, 10, 15, 21, ...] with [2, 4, 7, 11, 16, 22, ...]
%o A051747 (PARI) conv(u,v)=local(w); w=vector(length(u),i,sum(j=1,i,u[j]*v[i+1-j])); 
               w; t(n)=n*(n+1)/2; u=vector(10,i,t(i)); v=vector(10,i,t(i)+1); conv(u,
               v)
%Y A051747 Cf. A000217, A000389, A005583.
%Y A051747 Sequence in context: A162249 A156492 A090809 this_sequence A024456 A050927 
               A011921
%Y A051747 Adjacent sequences: A051744 A051745 A051746 this_sequence A051748 A051749 
               A051750
%K A051747 easy,nonn
%O A051747 1,1
%A A051747 Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Dec 07 1999