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-1, -2, 0, 16, 110, 708, 5026, 40304, 362862, 3628780, 39916778, 479001576, 6227020774, 87178291172, 1307674367970, 20922789887968, 355687428095966, 6402373705727964, 121645100408831962, 2432902008176639960, 51090942171709439958, 1124000727777607679956, 25852016738884976639954, 620448401733239439359952
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refs;
listen;
history;
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internal format)
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OFFSET
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1,2
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COMMENTS
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For n > 2, a(n) is the largest value of k such that (n!+k)/(n+k) is an integer.
For n > 2, a(n) is the largest value of k such that (n!+k)/(n+k) is prime.
For n > 1, a(n) is even.
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LINKS
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FORMULA
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a(n) = n!-2n.
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EXAMPLE
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3!-2*3 = 0 so a(3) = 0.
4!-2*4 = 16 so a(4) = 16.
5!-2*5 = 110 so a(5) = 110.
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PROG
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(Python)
import math
{print(math.factorial(n)-2*n) for n in range(1, 25)}
(PARI) for(n=1, 25, print(n!-2*n))
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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