Sum{T(n,k)}, k = 0,1,...,n, where T is the array defined in A024996.

Terms

a(0) =1a(1) =2a(2) =4a(3) =7a(4) =22a(5) =64a(6) =191a(7) =567a(8) =1689a(9) =5033a(10) =15013a(11) =44809a(12) =133816a(13) =399802a(14) =1194949a(15) =3572693a(16) =10684758a(17) =31962456a(18) =95633229a(19) =286193409a(20) =856610214a(21) =2564317356a(22) =7677475521a(23) =22988860305a(24) =68843627049a(25) =206183053485a(26) =617563017927