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A089327
Smallest prime p such that 10*n*p +1 is prime.
0
3, 2, 2, 7, 2, 3, 3, 3, 2, 7, 3, 2, 7, 2, 5, 13, 11, 3, 3, 2, 2, 3, 2, 5, 3, 2, 2, 31, 5, 2, 37, 2, 2, 3, 2, 5, 7, 2, 3, 3, 2, 11, 3, 2, 5, 3, 2, 7, 3, 11, 2, 13, 2, 3, 7, 5, 5, 3, 2, 2, 3, 3, 13, 7, 2, 2, 3, 2, 2, 31, 3, 3, 13, 2, 3, 3, 3, 3, 3, 2, 2, 7, 29, 3, 3, 2, 2, 31, 3, 2, 3, 17, 2, 7, 2, 5, 7, 11
OFFSET
1,1
EXAMPLE
31,41,61,281, etc. are primes.
MATHEMATICA
With[{prs=Prime[Range[100]]}, Table[SelectFirst[prs, PrimeQ[10n*#+1]&], {n, 100}]] (* The program uses the SelectFirst function from Mathematica version 10 *) (* Harvey P. Dale, Apr 27 2015 *)
CROSSREFS
Sequence in context: A299778 A302248 A235773 * A280851 A279391 A237270
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Nov 03 2003
EXTENSIONS
More terms from David Wasserman, Sep 13 2005
STATUS
approved