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A049646
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a(n) = T(n,n+1), array T given by A049639.
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1
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0, 1, 3, 4, 5, 7, 9, 11, 13, 17, 21, 23, 25, 31, 37, 41, 45, 51, 57, 61, 65, 75, 85, 89, 93, 105, 117, 123, 129, 137, 145, 153, 161, 177, 193, 199, 205, 223, 241, 249, 257, 269, 281, 291, 301, 323, 345, 353, 361, 381, 401, 413, 425, 443, 461, 473, 485, 513, 541, 549, 557
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OFFSET
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0,3
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LINKS
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MATHEMATICA
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a[0 | 1, 0 | 1] = 0; a[0 | 1, _] = a[_, 0 | 1] = 1; a[i_, j_] := Module[{slopes, cnt}, slopes = Union@Flatten@Table[(k - j)/(h - i), {h, 0, i - 1}, {k, 0, j - 1}]; cnt[slope_] := Count[Flatten[Table[{h, k}, {h, 0, i - 1}, {k, 0, j - 1}], 1], {h_, k_} /; (k - j)/(h - i) == slope]; Count[cnt /@ slopes, c_ /; c >= 2] + 2]; Table[a[n, n + 1], {n, 0, 25}] (* G. C. Greubel, Dec 07 2017 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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