a(n) = 1 + Sum_{k=0..n} (2*k - 1)*A349976(n, k).

Terms

a(0) =0a(1) =1a(2) =5a(3) =17a(4) =53a(5) =147a(6) =389a(7) =981a(8) =2401a(9) =5697a(10) =13293a(11) =30423a(12) =68745a(13) =153403a(14) =339195a(15) =743169a(16) =1617857a(17) =3497875a(18) =7523697a(19) =16102889a(20) =34324847a(21) =72875031a(22) =154233691a(23) =325388121a(24) =684664081a(25) =1436991619a(26) =3009410483a(27) =6289146455a(28) =13119434889a(29) =27319198507