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A191012
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a(n) = n^5 - n^4 + n^3 - n^2 + n.
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1
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0, 1, 22, 183, 820, 2605, 6666, 14707, 29128, 53145, 90910, 147631, 229692, 344773, 501970, 711915, 986896, 1340977, 1790118, 2352295, 3047620, 3898461, 4929562, 6168163, 7644120, 9390025, 11441326, 13836447, 16616908, 19827445
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OFFSET
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0,3
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COMMENTS
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n such that x^5 + x^4 + x^3 + x^2 + x + n factors over the integers.
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LINKS
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FORMULA
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G.f.: x*(5*x^4 + 32*x^3 + 66*x^2 + 16*x + 1)/(1-x)^6.
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EXAMPLE
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a(2) = 22 is in the sequence, because x^5 + x^4 + x^3 + x^2 + x + 22 = (x+2)*(x^4 - x^3 + 3*x^2 - 5*x + 11).
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MAPLE
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[seq(n*(n^4-n^3+n^2-n+1), n=0..25)];
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PROG
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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