Numbers with exactly 3 1's in base 5 expansion.

Terms

a(0) =31a(1) =131a(2) =151a(3) =155a(4) =157a(5) =158a(6) =159a(7) =161a(8) =166a(9) =171a(10) =181a(11) =206a(12) =231a(13) =281a(14) =406a(15) =531a(16) =631a(17) =651a(18) =655a(19) =657a(20) =658a(21) =659a(22) =661a(23) =666a(24) =671a(25) =681a(26) =706a(27) =731a(28) =751a(29) =755