Beta polynomials (coefficients in descending order, triangle read by rows).

Terms

a(0) =1a(1) =1a(2) =1a(3) =-1a(4) =1a(5) =-2a(6) =-2a(7) =1a(8) =-3a(9) =-3a(10) =5a(11) =1a(12) =-4a(13) =-4a(14) =16a(15) =16a(16) =1a(17) =-5a(18) =-5a(19) =35a(20) =35a(21) =-61a(22) =1a(23) =-6a(24) =-6a(25) =64a(26) =64a(27) =-272a(28) =-272a(29) =1