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A053502
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Number of degree-n permutations of order dividing 12.
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5
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1, 1, 2, 6, 24, 96, 576, 3312, 21456, 152784, 1237536, 9984096, 133494912, 1412107776, 16369357824, 206123325696, 2866280276736, 36809077162752, 592066290710016, 8800038127378944, 136876273991755776, 2197453620220010496, 37915306084793106432
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OFFSET
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0,3
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REFERENCES
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R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Example 5.2.10.
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LINKS
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FORMULA
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E.g.f.: exp(x + x^2/2 + x^3/3 + x^4/4 + x^6/6 + x^12/12).
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MAPLE
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a:= proc(n) option remember; `if`(n<0, 0, `if`(n=0, 1,
add(mul(n-i, i=1..j-1)*a(n-j), j=[1, 2, 3, 4, 6, 12])))
end:
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MATHEMATICA
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a[n_]:= a[n] = If[n<0, 0, If[n==0, 1, Sum[Product[n-i, {i, 1, j-1}]*a[n-j], {j, {1, 2, 3, 4, 6, 12}}]]]; Table[a[n], {n, 0, 25}] (* Jean-François Alcover, Apr 24 2014, after Alois P. Heinz *)
With[{m = 30}, CoefficientList[Series[Exp[x +x^2/2 +x^3/3 +x^4/4 +x^6/6 + x^12/12], {x, 0, m}], x]*Range[0, m]!] (* G. C. Greubel, May 15 2019 *)
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PROG
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(PARI) my(x='x+O('x^30)); Vec(serlaplace( exp(x + x^2/2 + x^3/3 + x^4/4 + x^6/6 + x^12/12) )) \\ G. C. Greubel, May 15 2019
(Magma) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!( Exp(x + x^2/2 + x^3/3 + x^4/4 + x^6/6 + x^12/12) )); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, May 15 2019
(Sage) m = 30; T = taylor(exp(x + x^2/2 + x^3/3 + x^4/4 + x^6/6 + x^12/12), x, 0, m); [factorial(n)*T.coefficient(x, n) for n in (0..m)] # G. C. Greubel, May 15 2019
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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