Odd integers k such that sigma(k)^2 is divisible by k.

Terms

a(0) =1a(1) =1521a(2) =5733a(3) =92781a(4) =108927a(5) =544635a(6) =628849a(7) =1886547a(8) =2069613a(9) =2723175a(10) =2876211a(11) =5659641a(12) =16978923a(13) =40847625a(14) =45623655a(15) =50936769a(16) =60998353a(17) =84418425a(18) =84894615a(19) =89162541a(20) =173369889a(21) =182995059a(22) =191166885a(23) =262840851a(24) =401164731a(25) =424473075a(26) =426988471