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A116759
Number of permutations of length n which avoid the patterns 2134, 3421, 4123.
0
1, 2, 6, 21, 71, 209, 533, 1205, 2473, 4696, 8372, 14169, 22959, 35855, 54251, 79865, 114785, 161518, 223042, 302861, 405063, 534381, 696257, 896909, 1143401, 1443716, 1806832, 2242801, 2762831, 3379371
OFFSET
1,2
FORMULA
G.f.: A(x) = -{(x^6-8x^5+15x^4-14x^3+13x^2-5x+1)x}/{(x-1)^7}
(n^6 + 5n^5 - 55n^4 + 195n^3 - 186n^2 + 40n + 240)/240. - Franklin T. Adams-Watters, Sep 16 2006
CROSSREFS
Sequence in context: A116766 A116825 A116767 * A116835 A294725 A116755
KEYWORD
nonn,easy
AUTHOR
Lara Pudwell, Feb 26 2006
STATUS
approved