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A341209
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a(n) = (n^3 + 6*n^2 + 17*n + 6)/6.
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0
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1, 5, 12, 23, 39, 61, 90, 127, 173, 229, 296, 375, 467, 573, 694, 831, 985, 1157, 1348, 1559, 1791, 2045, 2322, 2623, 2949, 3301, 3680, 4087, 4523, 4989, 5486, 6015, 6577, 7173, 7804, 8471, 9175, 9917, 10698, 11519, 12381, 13285, 14232, 15223, 16259, 17341, 18470, 19647
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OFFSET
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0,2
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COMMENTS
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Conjecture: Mark each point on a 7^k or 11^k grid with the number of points that are visible from the point; for n > 0, a(n) is the number of distinct values in both grids.
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LINKS
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FORMULA
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a(n) = (n^3 + 6*n^2 + 17*n + 6)/6.
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PROG
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(PARI) a(n) = (n^3 + 6*n^2 + 17*n + 6)/6;
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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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