Partial sums of A005985.

Terms

a(0) =0a(1) =1a(2) =5a(3) =14a(4) =46a(5) =111a(6) =303a(7) =688a(8) =1712a(9) =3761a(10) =8881a(11) =19122a(12) =43698a(13) =92851a(14) =207539a(15) =436916a(16) =961204a(17) =2009781a(18) =4369077a(19) =9087670a(20) =19573430a(21) =40544951a(22) =86682295a(23) =178956984a(24) =380283576a(25) =782936761a(26) =1655351993a(27) =3400182458a(28) =7158278842