Triangle read by rows: characteristic polynomials of Z/nZ addition tables considered as matrices.

Terms

a(0) =1a(1) =1a(2) =0a(3) =1a(4) =0a(5) =-1a(6) =1a(7) =-3a(8) =-3a(9) =9a(10) =1a(11) =-4a(12) =-20a(13) =32a(14) =96a(15) =1a(16) =-10a(17) =-25a(18) =250a(19) =125a(20) =-1250a(21) =1a(22) =-12a(23) =-93a(24) =576a(25) =2592a(26) =-5184a(27) =-19440a(28) =1a(29) =-21