Triangular array: the fusion of (x+1)^n and (x+2)^n; see Comments for the definition of fusion.

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =5a(5) =6a(6) =1a(7) =8a(8) =21a(9) =18a(10) =1a(11) =11a(12) =45a(13) =81a(14) =54a(15) =1a(16) =14a(17) =78a(18) =216a(19) =297a(20) =162a(21) =1a(22) =17a(23) =120a(24) =450a(25) =945a(26) =1053a(27) =486a(28) =1a(29) =20