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 A087522 a(0) = 2; for n>=1, a(n) = smallest prime p such that p+1 is divisible by an n-th power > 1. 15
 2, 2, 3, 7, 31, 31, 127, 127, 1279, 3583, 5119, 6143, 8191, 8191, 81919, 131071, 131071, 131071, 524287, 524287, 14680063, 14680063, 109051903, 109051903, 654311423, 738197503, 738197503, 2147483647, 2147483647, 2147483647, 2147483647 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Trivially the n-th power under consideration is 2^n for n > 1. LINKS John Mason, using Robert Israel's data for A127582, Table of n, a(n) for n = 0..3310 FORMULA a(n) << 37^n by Xylouris' improvement to Linnik's theorem. - Charles R Greathouse IV, Dec 10 2013 EXAMPLE a(1) = 2 because 3^1|3. a(2) = 3 because 2^2|4. a(3) = 7 because 2^3|8. PROG (PARI) okdivs(pp1, n) = fordiv(pp1, d, if ((d>1) && ispower(d, n), return (1))); 0 a(n) = {if (n == 0, return (2)); p = 2; while (! okdivs(p+1, n), p = nextprime(p+1)); return (p); } \\ Michel Marcus, Sep 14 2013 CROSSREFS A127582 is identical except for a(1). Sequence in context: A077001 A180996 A307503 * A092970 A052449 A053413 Adjacent sequences:  A087519 A087520 A087521 * A087523 A087524 A087525 KEYWORD nonn AUTHOR Amarnath Murthy, Sep 11 2003 EXTENSIONS More terms from Ray Chandler, Sep 14 2003 Edited by N. J. A. Sloane, Jul 03 2008 STATUS approved

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Last modified June 15 22:19 EDT 2019. Contains 324145 sequences. (Running on oeis4.)