Partial sums of A053739.

Terms

a(0) =1a(1) =7a(2) =29a(3) =92a(4) =247a(5) =591a(6) =1300a(7) =2683a(8) =5270a(9) =9955a(10) =18228a(11) =32551a(12) =56967a(13) =98086a(14) =166681a(15) =280271a(16) =467301a(17) =773906a(18) =1274856a(19) =2091266a(20) =3419252a(21) =5576298a(22) =9076280a(23) =14750858a(24) =23945893a(25) =38839257a(26) =62955061a(27) =101995694