Numbers with exactly 4 ones in binary expansion.

Terms

a(0) =15a(1) =23a(2) =27a(3) =29a(4) =30a(5) =39a(6) =43a(7) =45a(8) =46a(9) =51a(10) =53a(11) =54a(12) =57a(13) =58a(14) =60a(15) =71a(16) =75a(17) =77a(18) =78a(19) =83a(20) =85a(21) =86a(22) =89a(23) =90a(24) =92a(25) =99a(26) =101a(27) =102a(28) =105a(29) =106