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 A143965 Factorial eigentriangle: A119502 * (A051295 *0^(n-k)); 0 <= k <= n. 1
 1, 1, 1, 2, 1, 2, 6, 2, 2, 5, 24, 6, 4, 5, 15, 120, 24, 12, 10, 15, 54, 720, 120, 48, 30, 30, 54, 235, 5040, 720, 240, 120, 90, 108, 235, 1237, 40320, 5040, 1440, 600, 360, 324, 470, 1237, 7790 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS Triangle read by rows, termwise product of (n-k)! (i.e factorial decrescendo, A119502) and the INVERT transform of the factorials (A051295) prefaced by a 1: (1, 1, 2, 5, 15, 54, 235, 1237, 7790, ...). A119502 = (1; 1,1; 2,1,1; 6,2,1,1; 24,6,2,1,1; ...). The operation (A051295 * 0^(n-k)) with A051295 prefaced with a 1 = an infinite lower triangular matrix with (1, 1, 2, 5, 15, 54, 235, ...) in the main diagonal and the rest zeros. Row sums = the INVERT transform of the factorials, A051295: (1, 2, 5, 15, 54, 235, 1237, ...). Right border shifts A051295: (1, 1, 2, 5, 15, ...). Sum of n-th row terms = rightmost term of next row; e.g. ( 6 + 2 + 2 + 5) = 15. With offset 1 for n and k, T(n,k) counts permutations of [n] that contain a 132 pattern only as part of a 4132 pattern by position k of largest entry n. Example: T(5,3)=4 counts 34512, 34521, 43512, 43521. - David Callan, Nov 21 2011 From Gary W. Adamson, Jul 21 2016: (Start) A production matrix M for the reversal of the triangle is follows: M = 1, 1, 0, 0, 0, 0, ... 1, 0, 2, 0, 0, 0, ... 1, 0, 0, 3, 0, 0, ... 1, 0, 0, 0, 4, 0, ... 1, 0, 0, 0, 0, 5, ... ... Take powers of M, extracting the top row, getting: (1), (1, 1), (2, 1, 2), (5, 2, 2, 6), ... (End) LINKS Table of n, a(n) for n=0..44. FORMULA Factorial eigentriangle: A119502 * (A051295 *0^(n-k)); 0 <= k <= n. The operation uses A119502 prefaced with a 1 = (1, 1, 2, 5, 15, 54, 235, ...); i.e., the right border of the triangle. EXAMPLE First few rows of the triangle: 1; 1, 1; 2, 1, 2; 6, 2, 2, 5; 24, 6, 4, 5, 15; 120, 24, 12, 10, 15, 54; 720, 120, 48, 30, 30, 54, 235; 5040, 720, 240, 120, 90, 108, 235, 1737; ... Example: Row 3 = (6, 2, 2, 5) = termwise products of row 3 terms of triangle A119502 (6, 2, 1, 1) and the first four terms of (1, 1, 2, 5, ...) = (6*1, 2*1, 1*2, 1*5). CROSSREFS Cf. A000142, A051295, A119502. Sequence in context: A284466 A258615 A152431 * A182073 A328001 A347563 Adjacent sequences: A143962 A143963 A143964 * A143966 A143967 A143968 KEYWORD nonn,tabl AUTHOR Gary W. Adamson, Sep 06 2008 STATUS approved

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Last modified September 12 20:35 EDT 2024. Contains 375854 sequences. (Running on oeis4.)