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A328329
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Lesser of twin primes p such that d(p+1) > d(q+1) for all lessers of twin primes q < p, where d(n) is the number of divisors of n (A000005).
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0
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3, 5, 11, 29, 59, 179, 239, 419, 1319, 2339, 3119, 3359, 6299, 7559, 21599, 21839, 33599, 35279, 42839, 55439, 100799, 110879, 287279, 415799, 957599, 1621619, 1713599, 1867319, 1940399, 2489759, 3991679, 6652799, 11531519, 18258239, 22822799, 26732159, 28828799
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OFFSET
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1,1
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COMMENTS
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The corresponding values of d(p+1) are 3, 4, 6, 8, 12, 18, 20, 24, 32, 36, 40, 48, 54, 64, 72, 80, 84, 90, 96, 120, 126, 144, 160, 192, 216, 240, 252, 256, 270, 288, 320, 384, 432, 448, 480, 512, 576, ...
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LINKS
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MATHEMATICA
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dm = DivisorSigma[0, 4]; s = {3}; Do[If[!PrimeQ[6n - 1] || !PrimeQ[6n + 1], Continue[]]; d = DivisorSigma[0, 6n]; If[d > dm, dm = d; AppendTo[s, 6n - 1]], {n, 1, 10^5}]; s
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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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