Number of parts in all proper twice partitions of n into distinct parts.

Terms

a(0) =0a(1) =0a(2) =0a(3) =3a(4) =6a(5) =13a(6) =30a(7) =61a(8) =121a(9) =210a(10) =353a(11) =600a(12) =989a(13) =1628a(14) =2667a(15) =4205a(16) =6514a(17) =10406a(18) =15893a(19) =24322a(20) =37516a(21) =56824a(22) =85102a(23) =128420a(24) =191579a(25) =284898a(26) =422839a(27) =622721a(28) =913006a(29) =1345320