Number of multiples of 3 in 0..2^n-1 with an even sum of base-2 digits.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =6a(5) =10a(6) =20a(7) =35a(8) =70a(9) =126a(10) =252a(11) =463a(12) =926a(13) =1730a(14) =3460a(15) =6555a(16) =13110a(17) =25126a(18) =50252a(19) =97223a(20) =194446a(21) =379050a(22) =758100a(23) =1486675a(24) =2973350a(25) =5858126a(26) =11716252a(27) =23166783a(28) =46333566a(29) =91869970