Triangle read by rows: number of permutations of [1..n] with k progressions of rise 2, distance 1 and length 3 (n >= 0, k >= 0).

A216716

Triangle read by rows: number of permutations of [1..n] with k progressions of rise 2, distance 1 and length 3 (n >= 0, k >= 0).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =114a(6) =6a(7) =674a(8) =44a(9) =2a(10) =4714a(11) =294a(12) =30a(13) =2a(14) =37754a(15) =2272a(16) =276a(17) =16a(18) =2a(19) =340404a(20) =20006a(21) =2236a(22) =216a(23) =16a(24) =2a(25) =3412176a(26) =193896a(27) =20354a(28) =2200a(29) =156

External references