a(n) = p(2*n)-p(2*n-2)-p(n) where p(n) are the partition numbers A000041(n).

Terms

a(0) =0a(1) =1a(2) =3a(3) =6a(4) =13a(5) =24a(6) =43a(7) =74a(8) =124a(9) =200a(10) =319a(11) =496a(12) =760a(13) =1147a(14) =1710a(15) =2514a(16) =3664a(17) =5282a(18) =7548a(19) =10696a(20) =15044a(21) =20999a(22) =29128a(23) =40140a(24) =54995a(25) =74927a(26) =101556a(27) =136950a(28) =183832a(29) =245643