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A034111
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Fractional part of square root of a(n) starts with 5: first term of runs.
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1
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21, 31, 43, 57, 73, 91, 111, 133, 157, 183, 211, 241, 273, 307, 343, 381, 421, 463, 507, 553, 601, 651, 703, 757, 813, 871, 931, 993, 1057, 1123, 1191, 1261, 1333, 1407, 1483, 1561, 1641, 1723, 1807, 1893, 1981, 2071, 2163, 2257, 2353, 2451, 2551, 2653
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OFFSET
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1,1
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COMMENTS
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Agrees with sequence A002061 (n^2-n+1 = central polygonal numbers) starting with sixth term.
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LINKS
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FORMULA
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MATHEMATICA
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LinearRecurrence[{3, -3, 1}, {21, 31, 43}, 50] (* Harvey P. Dale, Apr 29 2022 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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