Triangle read by rows: T(n,k) is the number of permutations p of {1,2,...,n} such that the set {p(i)-i, i=1,2,...,n} has exactly k elements (1<=k<=n).
A125182
Triangle read by rows: T(n,k) is the number of permutations p of {1,2,...,n} such that the set {p(i)-i, i=1,2,...,n} has exactly k elements (1<=k<=n).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =3a(6) =1a(7) =4a(8) =12a(9) =7a(10) =1a(11) =4a(12) =38a(13) =54a(14) =23a(15) =1a(16) =8a(17) =77a(18) =248a(19) =303a(20) =83a(21) =1a(22) =6a(23) =160a(24) =824a(25) =2008a(26) =1636a(27) =405a(28) =1a(29) =11
External references
- oeis: A125182