Index position of {2}^n within the list of partitions of 2n in canonical ordering.

Terms

a(0) =1a(1) =1a(2) =3a(3) =8a(4) =18a(5) =37a(6) =71a(7) =128a(8) =223a(9) =376a(10) =617a(11) =991a(12) =1563a(13) =2423a(14) =3704a(15) =5589a(16) =8333a(17) =12293a(18) =17959a(19) =25996a(20) =37318a(21) =53153a(22) =75153a(23) =105535a(24) =147249a(25) =204201a(26) =281563a(27) =386128a(28) =526795a(29) =715191