Triangular array, read by rows: pairwise sums of trinomial array A027907.

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =1a(5) =3a(6) =4a(7) =3a(8) =1a(9) =1a(10) =4a(11) =8a(12) =10a(13) =8a(14) =4a(15) =1a(16) =1a(17) =5a(18) =13a(19) =22a(20) =26a(21) =22a(22) =13a(23) =5a(24) =1a(25) =1a(26) =6a(27) =19a(28) =40a(29) =61