1,1

a(n)=(1/2)*n*(1 + n)*(1 + 9*n + 27*n^2 + 42*n^3 + 36*n^4 + 18*n^5 + 6*n^6)

a(1)=139=2^2+...+7^2, a(2)=9^2+...+26^2.

Cf. A048396 Sum of consecutive noncubes.

Sequence in context: A142137 A001163 A140791 this_sequence A108317 A114825 A131492

Adjacent sequences: A158524 A158525 A158526 this_sequence A158528 A158529 A158530

nonn

Zak Seidov (zakseidov(AT)yahoo.com), Mar 20 2009