a(n) = Sum_{k=0..n} (k+1) * A026736(n,k).

Terms

a(0) =1a(1) =3a(2) =8a(3) =20a(4) =50a(5) =117a(6) =283a(7) =639a(8) =1512a(9) =3338a(10) =7774a(11) =16898a(12) =38884a(13) =83566a(14) =190488a(15) =405848a(16) =918120a(17) =1942813a(18) =4367665a(19) =9191499a(20) =20555546a(21) =43061789a(22) =95874233a(23) =200083005a(24) =443770612a(25) =923124007a(26) =2040635445a(27) =4233080627a(28) =9330343290