1,2

sum{k=1 to n} a(k) = A160690(n). d(A160689(n)) = d(A160690(n)) = A160691(n).

Table of n, a(n) for n=1..95.

Contribution from Farideh Firoozbakht, May 28 2009: (Start)

a[1]=1; a[n_]:=a[n]=(s=Sum[a[k], {k, n-1}]; For[m=1, DivisorSigma[0, m]!=

DivisorSigma[0, s+m], m++ ]; m); Table[a[n], {n, 95}] (End)

A160690, A160691

Sequence in context: A121258 A087421 A132697 * A179976 A137508 A055921

Adjacent sequences: A160686 A160687 A160688 * A160690 A160691 A160692

nonn

Leroy Quet, May 24 2009

More terms from Farideh Firoozbakht, May 28 2009

approved