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A061322
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a(n) = a(n-1) * (1 + a(n-1)/n^2) with a(0) = 2.
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1
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2, 6, 15, 40, 140, 924, 24640, 12415040, 2408343949440, 71606426901226335015040, 51274803735606705472274088614112357905277056, 21728144612603201307908899563300049012978385050783094682272184269369267136230071558272
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OFFSET
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0,1
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COMMENTS
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Only first 42 terms are integers (see A003504).
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LINKS
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FORMULA
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EXAMPLE
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a(2) = 6 * (1 + 6/2^2) = 15.
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PROG
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(PARI) {a(n) = local(x); if( n<1, 2 * (n==0), (x = a(n-1)) + (x/n)^2)} /* Michael Somos, Apr 02 2006 */
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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