Triangle read by rows: T(n,k) is the number of stretching pairs in all permutations in S_{n,k} (=set of permutations in S_n with k cycles) (n >= 3; 1 <= k <= n-2).
A216118
Triangle read by rows: T(n,k) is the number of stretching pairs in all permutations in S_{n,k} (=set of permutations in S_n with k cycles) (n >= 3; 1 <= k <= n-2).
Terms
- a(0) =0a(1) =1a(2) =1a(3) =10a(4) =15a(5) =5a(6) =90a(7) =165a(8) =90a(9) =15a(10) =840a(11) =1750a(12) =1225a(13) =350a(14) =35a(15) =8400a(16) =19180a(17) =15750a(18) =5950a(19) =1050a(20) =70a(21) =90720a(22) =222264a(23) =204624a(24) =92610a(25) =22050a(26) =2646a(27) =126a(28) =1058400a(29) =2744280
External references
- oeis: A216118