Numbers having three 7's in base 8.

Terms

a(0) =511a(1) =1023a(2) =1535a(3) =2047a(4) =2559a(5) =3071a(6) =3583a(7) =3647a(8) =3711a(9) =3775a(10) =3839a(11) =3903a(12) =3967a(13) =4031a(14) =4039a(15) =4047a(16) =4055a(17) =4063a(18) =4071a(19) =4079a(20) =4087a(21) =4088a(22) =4089a(23) =4090a(24) =4091a(25) =4092a(26) =4093a(27) =4094a(28) =4607a(29) =5119