0,4

If n even a(n) = n*(n+2)*(2*n^3+n^2-2*n+4)/160, if n odd a(n) = (n^2-1)*(2*n^3+5*n^2+2*n-5)/160.

A059859 := n->add(A002620(i)^2, i=0..n);

f1 := n->1/160*(n-1)*(1+n)*(2*n^3+5*n^2+2*n-5); f2 := n->1/160*n*(n+2)*(2*n^3+n^2-2*n+4); A059859 := n-> if n mod 2 = 0 then f2(n) else f1(n); fi;

Cf. A002620.

Sequence in context: A146854 A033275 A166464 this_sequence A146617 A112561 A143567

Adjacent sequences: A059856 A059857 A059858 this_sequence A059860 A059861 A059862

nonn

N. J. A. Sloane (njas(AT)research.att.com), Feb 26 2001