Numbers n such that sigma(n+1)=3*phi(n).

Terms

a(0) =1a(1) =4a(2) =5a(3) =9a(4) =10a(5) =21a(6) =32a(7) =34a(8) =45a(9) =55a(10) =65a(11) =68a(12) =70a(13) =129a(14) =153a(15) =160a(16) =176a(17) =183a(18) =203a(19) =245a(20) =340a(21) =370a(22) =407a(23) =441a(24) =550a(25) =580a(26) =635a(27) =741a(28) =765a(29) =806