Nonprimes k that divide sigma(k) + phi(k).

Terms

a(0) =1a(1) =312a(2) =560a(3) =588a(4) =1400a(5) =23760a(6) =59400a(7) =85632a(8) =147492a(9) =153720a(10) =556160a(11) =569328a(12) =1590816a(13) =2013216a(14) =3343776a(15) =4563000a(16) =4695456a(17) =9745728a(18) =12558912a(19) =22013952a(20) =23336172a(21) =30002960a(22) =45326160a(23) =52021242a(24) =75007400a(25) =113315400a(26) =137617728a(27) =153587720a(28) =402831360a(29) =699117024