a(n) = Sum_{d|n} d*sigma(n/d)^d.

Terms

a(0) =1a(1) =5a(2) =7a(3) =29a(4) =11a(5) =131a(6) =15a(7) =445a(8) =214a(9) =1315a(10) =23a(11) =6755a(12) =27a(13) =15475a(14) =5807a(15) =62589a(16) =35a(17) =207302a(18) =39a(19) =680419a(20) =116277a(21) =1948963a(22) =47a(23) =7702195a(24) =38936a(25) =20726659a(26) =2365954a(27) =72743987a(28) =59a(29) =227262211