sigma(n) is an additive inverse of n modulo phi(n).

Terms

a(0) =1a(1) =2a(2) =6a(3) =10a(4) =12a(5) =28a(6) =76a(7) =120a(8) =312a(9) =588a(10) =672a(11) =888a(12) =1060a(13) =1264a(14) =1656a(15) =14496a(16) =17900a(17) =22896a(18) =44676a(19) =71712a(20) =77688a(21) =95040a(22) =183600a(23) =233088a(24) =327424a(25) =411264a(26) =425376a(27) =446016a(28) =453258a(29) =655776