Numbers whose maximal base 4 run length is 3.

Terms

a(0) =21a(1) =42a(2) =63a(3) =64a(4) =84a(5) =86a(6) =87a(7) =106a(8) =127a(9) =128a(10) =149a(11) =168a(12) =169a(13) =171a(14) =191a(15) =192a(16) =213a(17) =234a(18) =252a(19) =253a(20) =254a(21) =257a(22) =258a(23) =259a(24) =277a(25) =298a(26) =319a(27) =320a(28) =336a(29) =337