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A140578
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A positive integer n is included if n is the smallest integer in a run of a plural number of consecutive integers all with the same number of divisors.
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1
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2, 14, 21, 26, 33, 38, 44, 57, 75, 85, 93, 98, 104, 116, 118, 122, 133, 135, 141, 145, 147, 158, 171, 177, 189, 201, 205, 213, 217, 230, 242, 253, 285, 296, 298, 301, 326, 332, 334, 344, 374, 381, 387, 393, 429, 434, 445, 453, 481, 501, 507, 514, 526, 537, 542
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OFFSET
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1,1
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COMMENTS
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All terms of this sequence are included in sequence A005237.
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LINKS
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EXAMPLE
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d(33) = d(34) = d(35), where d(n) is the number of divisors of n. And since d(32) does not equal d(33), d(33) is the first term of this run of similar values. So 33 is included in this sequence.
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MATHEMATICA
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(First /@ Select[ Split[ Table[ {DivisorSigma[0, n], n}, {n, 1, 600}], First[#1] == First[#2] &] , Length[#] > 1 &])[[All, 2]] (* Jean-François Alcover, Oct 07 2013 *)
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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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