Triangle read by rows: coefficients of harmonic-geometric polynomials.

Terms

a(0) =0a(1) =0a(2) =1a(3) =0a(4) =1a(5) =3a(6) =0a(7) =1a(8) =9a(9) =11a(10) =0a(11) =1a(12) =21a(13) =66a(14) =50a(15) =0a(16) =1a(17) =45a(18) =275a(19) =500a(20) =274a(21) =0a(22) =1a(23) =93a(24) =990a(25) =3250a(26) =4110a(27) =1764a(28) =0a(29) =1