Antidiagonal sums of square array A126885.

Terms

a(0) =1a(1) =3a(2) =7a(3) =15a(4) =32a(5) =72a(6) =178a(7) =494a(8) =1543a(9) =5373a(10) =20581a(11) =85653a(12) =383494a(13) =1833250a(14) =9301792a(15) =49857540a(16) =281193501a(17) =1663183383a(18) =10286884195a(19) =66365330811a(20) =445598473612