Numbers n such that phi(n) + phi(n+1) = sigma(n)/2.

Terms

a(0) =56a(1) =456a(2) =476a(3) =828a(4) =846a(5) =1196a(6) =2060a(7) =2780a(8) =4484a(9) =7530a(10) =9174a(11) =11420a(12) =11475a(13) =11865a(14) =13454a(15) =22154a(16) =34916a(17) =35385a(18) =52185a(19) =67308a(20) =105798a(21) =140895a(22) =168872a(23) =190840a(24) =219852a(25) =241892a(26) =244074a(27) =267225a(28) =303834a(29) =317564