Numbers k such that phi(k) divides (sigma(k+2) + sigma(k-2)).

Terms

a(0) =5a(1) =6a(2) =13a(3) =15a(4) =33a(5) =68a(6) =117a(7) =156a(8) =168a(9) =222a(10) =259a(11) =265a(12) =313a(13) =522a(14) =644a(15) =665a(16) =750a(17) =986a(18) =1065a(19) =1153a(20) =1178a(21) =1328a(22) =1351a(23) =1377a(24) =1447a(25) =1750a(26) =1812a(27) =1824a(28) =1976a(29) =2392