Triangle read by rows: T(n, k) is the number of permutations of size n that require exactly k iterations of the pop-stack sorting map to reach the identity, for n >= 1, 0 <= k <= n-1.
A359413
Triangle read by rows: T(n, k) is the number of permutations of size n that require exactly k iterations of the pop-stack sorting map to reach the identity, for n >= 1, 0 <= k <= n-1.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =2a(6) =1a(7) =7a(8) =8a(9) =8a(10) =1a(11) =15a(12) =26a(13) =46a(14) =32a(15) =1a(16) =31a(17) =80a(18) =191a(19) =262a(20) =155a(21) =1a(22) =63a(23) =234a(24) =735a(25) =1440a(26) =1737a(27) =830a(28) =1a(29) =127
External references
- oeis: A359413