Plaindromes: numbers whose digits in base 4 are in nondecreasing order.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =5a(5) =6a(6) =7a(7) =10a(8) =11a(9) =15a(10) =21a(11) =22a(12) =23a(13) =26a(14) =27a(15) =31a(16) =42a(17) =43a(18) =47a(19) =63a(20) =85a(21) =86a(22) =87a(23) =90a(24) =91a(25) =95a(26) =106a(27) =107a(28) =111a(29) =127