a(2*n+1) = 1+A131941(2*n+1). a(2*n) = A131941(2*n).

Terms

a(0) =2a(1) =3a(2) =9a(3) =16a(4) =30a(5) =47a(6) =73a(7) =104a(8) =146a(9) =195a(10) =257a(11) =328a(12) =414a(13) =511a(14) =625a(15) =752a(16) =898a(17) =1059a(18) =1241a(19) =1440a(20) =1662a(21) =1903a(22) =2169a(23) =2456a(24) =2770a(25) =3107a(26) =3473a(27) =3864a(28) =4286a(29) =4735