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A111144
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a(n) = n*(n+13)*(n+14)/6.
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1
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0, 35, 80, 136, 204, 285, 380, 490, 616, 759, 920, 1100, 1300, 1521, 1764, 2030, 2320, 2635, 2976, 3344, 3740, 4165, 4620, 5106, 5624, 6175, 6760, 7380, 8036, 8729, 9460, 10230, 11040, 11891, 12784, 13720, 14700, 15725, 16796, 17914, 19080, 20295, 21560
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OFFSET
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0,2
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COMMENTS
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Analogous to A111396 n(n+7)(n+8)/6 and A000292 expressed as n(n+1)(n+2)/6. a(13) = 1521 = 39^2. a(14) = 1764 = 42^2. After a(1) all values have at least three prime factors with multiplicity, for example a(33) = 11891 = 11 * 23 * 47 and a(49) = 31899 = 3 * 7^3 * 31.
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LINKS
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FORMULA
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G.f.: x*(35 - 60*x + 26*x^2)/(1-x)^4. [Colin Barker, Jan 11 2012]
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MATHEMATICA
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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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