Antidiagonal sums in A101321.

Terms

a(0) =1a(1) =2a(2) =4a(3) =9a(4) =20a(5) =41a(6) =77a(7) =134a(8) =219a(9) =340a(10) =506a(11) =727a(12) =1014a(13) =1379a(14) =1835a(15) =2396a(16) =3077a(17) =3894a(18) =4864a(19) =6005a(20) =7336a(21) =8877a(22) =10649a(23) =12674a(24) =14975a(25) =17576a(26) =20502a(27) =23779a(28) =27434a(29) =31495