Triangle giving coefficients of ménage hit polynomials.

Terms

a(0) =1a(1) =1a(2) =0a(3) =1a(4) =1a(5) =0a(6) =1a(7) =3a(8) =1a(9) =1a(10) =1a(11) =6a(12) =6a(13) =8a(14) =3a(15) =1a(16) =10a(17) =20a(18) =38a(19) =35a(20) =16a(21) =1a(22) =15a(23) =50a(24) =134a(25) =213a(26) =211a(27) =96a(28) =1a(29) =21