1,2

For p prime: a(p) = 1+p+p^2, a(A000040(k))=A060800(k).

a(n) = 1/2*(sigma_1(n)^2+sigma_2(n)), cf. A000203, A001157.

a(6) = 1*1+1*2+1*3+1*6+2*2+2*3+2*6+3*3+3*6+6*6 = 1+2+3+6+4+6+12+9+18+36 = 97.

Sequence in context: A061204 A060983 A001001 this_sequence A117706 A066673 A088985

Adjacent sequences: A067689 A067690 A067691 this_sequence A067693 A067694 A067695

nonn

Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Feb 04, 2002