Triangle T(n,k) (0 <= k <= n) read by rows, arising from the study of rook polynomials.

Terms

a(0) =1a(1) =1a(2) =3a(3) =1a(4) =6a(5) =7a(6) =1a(7) =9a(8) =22a(9) =14a(10) =1a(11) =12a(12) =46a(13) =64a(14) =26a(15) =1a(16) =15a(17) =79a(18) =177a(19) =162a(20) =46a(21) =1a(22) =18a(23) =121a(24) =380a(25) =571a(26) =374a(27) =79a(28) =1a(29) =21