Partial sums of A048655.

Terms

a(0) =1a(1) =6a(2) =17a(3) =44a(4) =109a(5) =266a(6) =645a(7) =1560a(8) =3769a(9) =9102a(10) =21977a(11) =53060a(12) =128101a(13) =309266a(14) =746637a(15) =1802544a(16) =4351729a(17) =10506006a(18) =25363745a(19) =61233500a(20) =147830749a(21) =356895002a(22) =861620757a(23) =2080136520a(24) =5021893801a(25) =12123924126a(26) =29269742057a(27) =70663408244a(28) =170596558549a(29) =411856525346