cp's OEIS Frontend

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.

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A347492 Irregular triangle read by rows: T(n, k) is the q-multinomial coefficient defined by the k-th partition of n in Abramowitz-Stegun order, evaluated at q = 11.

Original entry on oeis.org

1, 1, 12, 1, 133, 1596, 1, 1464, 16226, 194712, 2336544, 1, 16105, 1964810, 23577720, 261319730, 3135836760, 37630041120, 1, 177156, 237758115, 2617126920, 2853097380, 348077880360, 3857863173990, 4176934564320, 46294358087880, 555532297054560, 6666387564654720, 1, 1948717
Offset: 1

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Author

Álvar Ibeas, Sep 03 2021

Keywords

Comments

Abuse of notation: we write T(n, L) for T(n, k), where L is the k-th partition of n in A-St order.
For any permutation (e_1,...,e_r) of the parts of L, T(n, L) is the number of chains of subspaces 0 < V_1 < ··· < V_r = (F_11)^n with dimension increments (e_1,...,e_r).

Examples

			The number of subspace chains 0 < V_1 < V_2 < (F_11)^3 is 1596 = T(3, (1, 1, 1)). There are 133 = A022175(3, 1) choices for a one-dimensional subspace V_1 and, for each of them, 12 = A022175(2, 1) extensions to a two-dimensional subspace V_2.
Triangle begins:
  k:  1    2     3      4       5
      ---------------------------
n=1:  1
n=2:  1   12
n=3:  1  133  1596
n=4:  1 1464 16226 194712 2336544
		

References

  • R. P. Stanley, Enumerative Combinatorics (vol. 1), Cambridge University Press (1997), Section 1.3.

Crossrefs

Cf. A036038 (q = 1), A022175, A015011 (last entry in each row).

Formula

T(n, (n)) = 1. T(n, L) = A022175(n, e) * T(n - e, L \ {e}), if L is a partition of n and e < n is a part of L.
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