Triangle read by rows: T(n,k) is the number of permutations of [n+1] with index in the lexicographic ordering of permutations being congruent to 1 or 5 modulo 6 that have exactly k descents; k > 0.
A318408
Triangle read by rows: T(n,k) is the number of permutations of [n+1] with index in the lexicographic ordering of permutations being congruent to 1 or 5 modulo 6 that have exactly k descents; k > 0.
Terms
- a(0) =0a(1) =0a(2) =1a(3) =1a(4) =1a(5) =1a(6) =6a(7) =1a(8) =1a(9) =19a(10) =19a(11) =1a(12) =1a(13) =48a(14) =142a(15) =48a(16) =1a(17) =1a(18) =109a(19) =730a(20) =730a(21) =109a(22) =1a(23) =1a(24) =234a(25) =3087a(26) =6796a(27) =3087a(28) =234a(29) =1
External references
- oeis: A318408