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A076666
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Numbers n such that sigma(n) + sigma(n+3) = sigma(n+1) + sigma(n+2).
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1
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2012, 2096, 15892, 17888, 39916, 102784, 141008, 146227, 482144, 487865, 1321312, 1887008, 2749057, 3513881, 7141158, 16767172, 17503912, 28122834, 30534728, 37453779, 42140437, 60994100, 67777337, 78251933, 113091820, 113768920, 129868059, 199240914, 240859196, 302897372
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OFFSET
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1,1
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COMMENTS
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Each term of the sequence marks the start of four consecutive sigma-values for which the sum of the means equals the sum of the extremes.
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LINKS
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EXAMPLE
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sigma(2012) + sigma(2015) = 3528 + 2688 = 6216; sigma(2013) + sigma(2014) = 2976 + 3240 = 6216, so 2012 is a term of the sequence.
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MATHEMATICA
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Select[Range[10^5], DivisorSigma[1, # ] + DivisorSigma[1, # + 3] == DivisorSigma[1, # + 1] + DivisorSigma[1, # + 2] &]
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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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