Composite n such that phi(n) * sigma(n) is one less than a square.

Terms

a(0) =6a(1) =22a(2) =33a(3) =44a(4) =69a(5) =76a(6) =82a(7) =140a(8) =190a(9) =295a(10) =354a(11) =392a(12) =423a(13) =451a(14) =531a(15) =581a(16) =650a(17) =944a(18) =1072a(19) =1119a(20) =1142a(21) =1150a(22) =1668a(23) =2276a(24) =2893a(25) =4043a(26) =4163a(27) =4176a(28) =4192a(29) =4257