Numbers k such that phi(k-6) = phi(k) = phi(k+6).

Terms

a(0) =78a(1) =84a(2) =222a(3) =228a(4) =438a(5) =738a(6) =948a(7) =1158a(8) =3252a(9) =5058a(10) =5268a(11) =6918a(12) =7212a(13) =7362a(14) =8082a(15) =8292a(16) =9732a(17) =12108a(18) =13842a(19) =14562a(20) =15348a(21) =15558a(22) =15858a(23) =17148a(24) =17502a(25) =18372a(26) =22482a(27) =23202a(28) =26148a(29) =26652