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A103959 Minimum prime p such that prime(n)*p-2 is prime. +0
2
2, 3, 3, 3, 3, 3, 5, 7, 3, 11, 13, 3, 11, 3, 3, 3, 5, 3, 3, 3, 7, 19, 11, 5, 7, 5, 3, 23, 7, 3, 3, 5, 3, 7, 5, 31, 7, 3, 3, 5, 17, 3, 3, 3, 5, 19, 3, 7, 29, 7, 5, 5, 61, 3, 3, 3, 11, 3, 3, 11, 7, 3, 3, 5, 3, 5, 3, 3, 3, 7, 11, 11, 19, 3, 61, 5, 29, 7, 3, 7, 17, 13, 3, 3, 61, 3, 5, 13, 3, 67, 3, 5, 3, 3 (list; graph; listen)
OFFSET

1,1

COMMENT

Conjecture: a(n)<prime(n). Tested hold up to n=10000

EXAMPLE

Prime(1)*2-2=2 is prime, so a(1)=2;

Prime(2)*3-2=7 is prime, so a(2)=3;

MATHEMATICA

Do[p=Prime[n]; k=1; pk=Prime[k]; cp=p*pk-2; While[ !PrimeQ[cp], k=k+1; pk=Prime[k]; cp=p*pk-2]; Print[pk], {n, 1, 10000}]

CROSSREFS

Sequence in context: A052288 A055767 A029110 this_sequence A035375 A093493 A087162

Adjacent sequences: A103956 A103957 A103958 this_sequence A103960 A103961 A103962

KEYWORD

base,easy,nonn

AUTHOR

Lei Zhou (lzhou5(AT)emory.edu), Feb 22 2005

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Last modified September 6 16:04 EDT 2008. Contains 143483 sequences.


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