Variation on Delannoy array/triangle; based on a triangular sum with the base multiplied by 2.

Terms

a(0) =1a(1) =2a(2) =2a(3) =4a(4) =9a(5) =4a(6) =8a(7) =28a(8) =28a(9) =8a(10) =16a(11) =76a(12) =121a(13) =76a(14) =16a(15) =32a(16) =192a(17) =422a(18) =422a(19) =192a(20) =32a(21) =64a(22) =464a(23) =1304a(24) =1809a(25) =1304a(26) =464a(27) =64a(28) =64a(29) =464