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A193563
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a(0) = 0, a(n) = n^2 * (a(n-1) + 1).
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2
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0, 1, 8, 81, 1312, 32825, 1181736, 57905113, 3705927296, 300180111057, 30018011105800, 3632179343801921, 523033825507476768, 88392716510763573961, 17324972436109660496552, 3898118798124673611724425, 997918412319916444601453056
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) = (n!)^2 * Sum_{k=0..n} (k/k!)^2.
a(n) = n^2 * A006040(n-1) for n > 0. (End)
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MAPLE
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seq(n!^2*add(1/k!^2, k=0..n-1), n=0..16); # Mark van Hoeij, May 13 2013
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PROG
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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