A244889 Second column of triangle in A244888.
1, -6, 36, -229, 1574, -11706, 93831
Offset: 2
Links
- Jeffrey B. Remmel, Consecutive Up-down Patterns in Up-down Permutations, Electron. J. Combin., 21 (2014), #P3.2.
This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
nmax = 24; A[] = 0; Do[A[x] = 1 - x A[x/(1 - x)^2]/(1 - x) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x] a[0] = 1; a[n_] := a[n] = -Sum[Binomial[n + k - 1, n - k - 1] a[k], {k, 0, n - 1}]; Table[a[n], {n, 0, 24}]
Triangle begins
1;
1, 1;
2, 1, 1;
6, 4, 1, 1;
23, 15, 6, 1, 1;
106, 68, 28, 8, 1, 1;
567, 365, 145, 45, 10, 1, 1;
3434, 2215, 877, 262, 66, 12, 1, 1;
23137, 14917, 5936, 1750, 427, 91, 14, 1, 1;
171174, 110324, 43936, 13020, 3108, 648, 120, 16, 1, 1;
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