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A245502
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Number of endofunctions f on [n] such that f^6(i) = f(i) for all i in [n].
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2
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1, 1, 3, 10, 41, 220, 1921, 25474, 384113, 5785192, 85295105, 1244587246, 18399553801, 286188407116, 4920039471089, 96938148715090, 2172951409994081, 53076309208887760, 1351935357372173953, 35000099470802409814, 914038174404012874745, 24209598764577808155316
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OFFSET
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0,3
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LINKS
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FORMULA
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E.g.f.: exp(x*exp(x)+x^5*exp(x)^5/5).
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MAPLE
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egf:= exp(x*exp(x)+x^5*exp(x)^5/5):
a:= n-> n!*coeff(series(egf, x, n+1), x, n):
seq(a(n), n=0..25);
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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_Alois P. Heinz_, Jul 24 2014
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STATUS
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approved
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