a(n) = T(n,0) + T(n,1) + ... + T(n,[ n/2 ]), T given by A026907.

Terms

a(0) =1a(1) =13a(2) =72a(3) =136a(4) =419a(5) =700a(6) =1851a(7) =3028a(8) =7564a(9) =12412a(10) =30209a(11) =50020a(12) =119942a(13) =200524a(14) =475853a(15) =802612a(16) =1888976a(17) =3211036a(18) =7504737a(19) =12844804a(20) =29838451a(21) =51379948a(22) =118713767a(23) =205520596a(24) =472568449a(25) =822083260a(26) =1882043403