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A055586
Sixth column of triangle A055584.
3
1, 10, 59, 268, 1037, 3598, 11535, 34832, 100369, 278546, 749587, 1966100, 5046293, 12714006, 31522839, 77070360, 186122265, 444596250, 1051721755, 2466250780, 5737807901, 13254000670, 30417092639, 69390565408
OFFSET
0,2
LINKS
A. F. Y. Zhao, Pattern Popularity in Multiply Restricted Permutations, Journal of Integer Sequences, 17 (2014), #14.10.3.
FORMULA
G.f.: 1/(((1-x)^2)*(1-2*x)^4).
a(n) = A055584(n+5, 5).
a(n) = Sum_{j=0..n-1} a(j) + A055582(n) for n >= 1.
E.g.f.: exp(x)*(x + 9) + 8*exp(2*x)*(2*x^3 + 3*x^2 + 6*x - 3)/3. - Stefano Spezia, Sep 24 2024
PROG
(PARI) Vec(1/(((1-x)^2)*(1-2*x)^4) + O(x^40)) \\ Michel Marcus, Dec 11 2015
CROSSREFS
Cf. A055584.
Partial sums of A027608.
Sequence in context: A045950 A226796 A061001 * A326827 A054489 A219580
KEYWORD
easy,nonn
AUTHOR
Wolfdieter Lang, May 26 2000
STATUS
approved