Number T(n,k) of permutations p of [n] such that |{ j : |p(j)-j| = 1 }| = k; triangle T(n,k), n >= 0, 0 <= k <= n, read by rows.
A320582
Number T(n,k) of permutations p of [n] such that |{ j : |p(j)-j| = 1 }| = k; triangle T(n,k), n >= 0, 0 <= k <= n, read by rows.
Terms
- a(0) =1a(1) =1a(2) =0a(3) =1a(4) =0a(5) =1a(6) =2a(7) =0a(8) =4a(9) =0a(10) =5a(11) =6a(12) =10a(13) =2a(14) =1a(15) =21a(16) =36a(17) =42a(18) =12a(19) =9a(20) =0a(21) =117a(22) =226a(23) =219a(24) =104a(25) =47a(26) =6a(27) =1a(28) =792a(29) =1568
External references
- oeis: A320582