a(n) = Sum_{k=1..n} binomial(n, k) (mod 2^k).

Terms

a(0) =1a(1) =1a(2) =5a(3) =7a(4) =11a(5) =29a(6) =37a(7) =67a(8) =115a(9) =225a(10) =353a(11) =635a(12) =719a(13) =2321a(14) =3417a(15) =3959a(16) =7071a(17) =9301a(18) =22973a(19) =35231a(20) =62315a(21) =71029a(22) =246613a(23) =338987a(24) =544675a(25) =855673a(26) =1775777a(27) =2960467a(28) =3427695a(29) =7422841