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A053505
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Number of degree-n permutations of order dividing 30.
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35
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1, 1, 2, 6, 18, 90, 540, 3060, 20700, 145980, 1459800, 13854600, 140059800, 1514748600, 15869034000, 285268878000, 4109761962000, 59488383690000, 935767530036000, 13364309726748000, 240338216104020000, 4540941256642020000, 79739974380153240000
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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^5/5 + x^6/6 + x^10/10 + x^15/15 + x^30/30).
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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, 5, 6, 10, 15, 30])))
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, 5, 6, 10, 15, 30}}]]]; Table[a[n], {n, 0, 25}] (* Jean-François Alcover, Mar 03 2014, after Alois P. Heinz *)
With[{m = 30}, CoefficientList[Series[Exp[x +x^2/2 +x^3/3 +x^5/5 +x^6/6 + x^10/10 +x^15/15 +x^30/30], {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^5/5 + x^6/6 +x^10/10 +x^15/15 +x^30/30) )) \\ 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^5/5 +x^6/6 +x^10/10 +x^15/15 +x^30/30) )); [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^5/5 +x^6/6 +x^10/10 +x^15/15 +x^30/30), 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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