Put a [+] b = A(A(a) + A(b)), where A = A007913; a(n) is the [+]-sum of binomial(n,i), i=0,...,n.

Terms

a(0) =1a(1) =2a(2) =1a(3) =2a(4) =1a(5) =2a(6) =3a(7) =2a(8) =1a(9) =1a(10) =6a(11) =38a(12) =167a(13) =2095a(14) =1a(15) =2030a(16) =3a(17) =15a(18) =21a(19) =138a(20) =263a(21) =2a(22) =57a(23) =1266a(24) =3470a(25) =7a(26) =145742a(27) =10a(28) =4682335a(29) =110