Partial sums of A045618.

Terms

a(0) =1a(1) =7a(2) =30a(3) =102a(4) =303a(5) =825a(6) =2116a(7) =5200a(8) =12381a(9) =28779a(10) =65658a(11) =147594a(12) =327835a(13) =721069a(14) =1573056a(15) =3408084a(16) =7340265a(17) =15728895a(18) =33554710a(19) =71303470a(20) =150995271a(21) =318767457a(22) =671089020a(23) =1409286552a(24) =2952790453a(25) =6174015955a(26) =12884902386