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A052578
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a(0) = 0, a(n) = 4*n! for n > 0.
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1
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0, 4, 8, 24, 96, 480, 2880, 20160, 161280, 1451520, 14515200, 159667200, 1916006400, 24908083200, 348713164800, 5230697472000, 83691159552000, 1422749712384000, 25609494822912000, 486580401635328000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 522
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FORMULA
| E.g.f.: -4*x/(-1+x)
Recurrence: {a(0)=0, (-1-n)*a(n)+a(n+1), a(1)=4}
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MAPLE
| spec := [S, {S=Prod(Union(Z, Z, Z, Z), Sequence(Z))}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
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MATHEMATICA
| Join[{0}, 4Range[25]!] (* From Harvey P. Dale, Mar 12 2011 *)
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PROG
| (PARI) a(n)=if(n, 4*n!, 0) \\ Charles R Greathouse IV, Nov 20 2011
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CROSSREFS
| Sequence in context: A010366 A008950 A045881 * A066631 A090896 A131637
Adjacent sequences: A052575 A052576 A052577 * A052579 A052580 A052581
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KEYWORD
| easy,nonn
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AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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