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A093679
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Sequence contains no 3-term arithmetic progression, starting with 1, 10.
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10
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1, 10, 11, 13, 14, 20, 22, 23, 28, 37, 38, 40, 41, 47, 49, 50, 82, 91, 92, 94, 95, 101, 103, 104, 109, 118, 119, 121, 122, 128, 130, 131, 244, 253, 254, 256, 257, 263, 265, 266, 271, 280, 281, 283, 284, 290, 292, 293, 325, 334, 335, 337, 338, 344, 346, 347
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OFFSET
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1,2
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COMMENTS
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a(1)=1, a(2)=10; a(n) is least k such that no three terms of a(1), a(2), ..., a(n-1), k form an arithmetic progression.
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LINKS
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FORMULA
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a(n) = (Sum_{k=1..n-1} (3^A007814(k) + 1)/2) + f(n), with f(n) an 8-periodic function with values {1, 9, 8, 9, 5, 10, 10, 10, ...}, n >= 1, as proved by Lawrence Sze.
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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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