Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having exactly k odd fixed points (0 <= k <= ceiling(n/2)).

A161133

Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having exactly k odd fixed points (0 <= k <= ceiling(n/2)).

Terms

    a(0) =1a(1) =0a(2) =1a(3) =1a(4) =1a(5) =3a(6) =2a(7) =1a(8) =14a(9) =8a(10) =2a(11) =64a(12) =42a(13) =12a(14) =2a(15) =426a(16) =234a(17) =54a(18) =6a(19) =2790a(20) =1704a(21) =468a(22) =72a(23) =6a(24) =24024a(25) =12864a(26) =3024a(27) =384a(28) =24a(29) =205056

External references