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A369626
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a(n) is the number of permutations of [n] which avoid the patterns 1234, 1324, and 2413.
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1
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1, 1, 2, 6, 21, 75, 265, 925, 3201, 11017, 37793, 129393, 442497, 1512225, 5165953, 17643457, 60250113, 205729921, 702452225, 2398414593, 8188884993
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OFFSET
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0,3
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LINKS
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EXAMPLE
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All 6 of the permutations of length 3 avoid all patterns of length 4, so a(3)=6.
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CROSSREFS
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Cf. A033321 (avoiding 1234, 1324, and 1342), A369431 (avoiding 1234, 1324, 1342, and 2413).
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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