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Search: id:A051887
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| A051887 |
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Minimal and special 2k-Germain primes, where 2k is A002110, primorial number. |
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+0
5
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| 2, 2, 2, 2, 2, 5, 17, 11, 11, 11, 2, 23, 7, 43, 19, 3, 5, 2, 7, 3, 61, 53, 2, 41, 47, 2
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Minimal p sequence so that primorial*p+1 is also prime.
While p is in A005384, the Q(n)p+1 primes are in A005385(primorial-safe primes)
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FORMULA
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Analogous to or subset of A051686, where the even numbers are: 2, 6, ..., A002110(n), ...
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EXAMPLE
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a(25) is 47 because Q(25)*47+1 is also prime and minimal with this property: Q(25)*47+1=47*2305567963945518424753102147331756070+1 =108361694305439365963395800924592535291 is a minimal prime. The first 6 terms (2,2,2,2,2,5) correspond to first entries in A005384, A007693, A051645, A051647, A051653, A051654 respectively.
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CROSSREFS
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A002110, A005384, A005385, A051686, A007693, A051886, A051888.
Sequence in context: A162487 A115101 A023569 this_sequence A139516 A160762 A112968
Adjacent sequences: A051884 A051885 A051886 this_sequence A051888 A051889 A051890
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Dec 15 1999
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