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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..98.

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

Adjacent sequences: A089324 A089325 A089326 * A089328 A089329 A089330

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy, Nov 03 2003

EXTENSIONS

More terms from David Wasserman, Sep 13 2005

STATUS

approved

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Last modified December 4 02:16 EST 2022. Contains 358544 sequences. (Running on oeis4.)