a(n)=sigma(A128607(n)), where A128607(n) is the sequence of perfect (or pure) powers such that a(n) is a perfect power.

A128608

a(n)=sigma(A128607(n)), where A128607(n) is the sequence of perfect (or pure) powers such that a(n) is a perfect power.

Terms

    a(0) =1a(1) =121a(2) =400a(3) =961a(4) =116281a(5) =2989441a(6) =7958041a(7) =361722361a(8) =962922961a(9) =1902442689a(10) =1891467081a(11) =5168743489a(12) =4755619521a(13) =5215583961a(14) =6835486329a(15) =7496615889a(16) =13884144561a(17) =13884144561a(18) =35018011161a(19) =120776405841a(20) =120776405841a(21) =230195565369a(22) =253358202409a(23) =171651947481

External references