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Search: id:A085067
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| A085067 |
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a(1) = 6, a(n) = smallest number of the form k*a(n-1) +1 with the same number of divisors i.e. 4. |
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1
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| 6, 55, 111, 334, 335, 671, 1343, 16117, 16118, 64473, 64474, 257897, 2063177, 8252709, 41263546, 123790639, 371371918, 1485487673, 2970975347, 59419506941, 356517041647, 5704272666353, 11408545332707, 262396542652262
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OFFSET
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1,1
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COMMENT
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Though the initial terms match, this sequence differs from A085066, in that the terms can be of two prime signatures i.e. p*q and p^3 such that tau(p*q) = tau(p^3) = 4.
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MATHEMATICA
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v = 6; Print[v]; Do[k = 1; While[DivisorSigma[0, k*v + 1] != 4, k++ ]; v = k*v + 1; Print[v], {n, 2, 30}] (Propper)
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CROSSREFS
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Cf. A085066.
Sequence in context: A119220 A119218 A085066 this_sequence A069508 A079465 A061792
Adjacent sequences: A085064 A085065 A085066 this_sequence A085068 A085069 A085070
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy and Meenakshi Srikanth (amarnath_murthy(AT)yahoo.com), Jun 29 2003
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EXTENSIONS
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Corrected and extended by Ryan Propper (rpropper(AT)stanford.edu), Aug 29 2005
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