First partial sums of A048745; second partial sums of A048654.

Terms

a(0) =1a(1) =6a(2) =20a(3) =56a(4) =145a(5) =362a(6) =888a(7) =2160a(8) =5233a(9) =12654a(10) =30572a(11) =73832a(12) =178273a(13) =430418a(14) =1039152a(15) =2508768a(16) =6056737a(17) =14622294a(18) =35301380a(19) =85225112a(20) =205751665a(21) =496728506a(22) =1199208744a(23) =2895146064a(24) =6989500945a(25) =16874148030a(26) =40737797084a(27) =98349742280a(28) =237437281729a(29) =573224305826