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A060836
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Number of permutations of n letters where exactly 5 change position.
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3
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0, 0, 0, 0, 44, 264, 924, 2464, 5544, 11088, 20328, 34848, 56628, 88088, 132132, 192192, 272272, 376992, 511632, 682176, 895356, 1158696, 1480556, 1870176, 2337720, 2894320, 3552120, 4324320, 5225220, 6270264, 7476084, 8860544
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OFFSET
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1,5
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LINKS
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FORMULA
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a(n) = 44*C(n, 5). a(n) = a(n-1)*n/(n-5).
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EXAMPLE
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a(8) = a(7) x 8/(8-5) = 924 x 8/3 = 2464
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PROG
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(PARI) { for (n=1, 1000, if (n>5, a*=n/(n - 5), if (n<5, a=0, a=44)); write("b060836.txt", n, " ", a); ) } \\ Harry J. Smith, Jul 19 2009
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CROSSREFS
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For changing 0, 1, 2, 3, 4, 5, n-4, n elements see A000012, A000004, A000217 (offset), A007290, A060008, A060836, A000475, A000166. Also see A000332, A008290.
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KEYWORD
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nonn,easy
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AUTHOR
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Robert Goodhand (rgoodhand(AT)hotmail.com), May 12 2001
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STATUS
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approved
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