Numbers k such that phi(k+1) = 4*phi(k).

Terms

a(0) =1260a(1) =13650a(2) =17556a(3) =18720a(4) =24510a(5) =42120a(6) =113610a(7) =244530a(8) =266070a(9) =712080a(10) =749910a(11) =795690a(12) =992250a(13) =1080720a(14) =1286730a(15) =1458270a(16) =1849470a(17) =2271060a(18) =2457690a(19) =3295380a(20) =3370770a(21) =3414840a(22) =3714750a(23) =4061970a(24) =4736490a(25) =5314050a(26) =5827080a(27) =6566910a(28) =6935082a(29) =7303980