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A224869
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a(n) = n*( a(n-1)+1 ), initialized by a(1) = -1.
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2
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-1, 0, 3, 16, 85, 516, 3619, 28960, 260649, 2606500, 28671511, 344058144, 4472755885, 62618582404, 939278736075, 15028459777216, 255483816212689, 4598708691828420, 87375465144739999, 1747509302894800000, 36697695360790800021, 807349297937397600484
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,3
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LINKS
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FORMULA
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a(n) +(-n-2)*a(n-1) +(2*n-1)*a(n-2) +(-n+2)*a(n-3)=0. - R. J. Mathar, Jul 28 2013
a(n) = exp(1)*n*Gamma(n,1) - 2*Gamma(n+1,0). - Martin Clever Mar 27 2023
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EXAMPLE
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a(4) = 4*(a(3)+1) = 4*4 = 16.
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MATHEMATICA
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PROG
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(Python)
a=-1
for n in range(2, 24):
print str(a)+', ',
a= n*(a+1)
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CROSSREFS
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KEYWORD
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sign,easy
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AUTHOR
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STATUS
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approved
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