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 A215961 Number of primes of the form 1 + b^8192 for 1 < b < 10^n. 0
 0, 0, 0, 0, 3, 74, 621 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS Primes 1 + b^8192 are a form of generalized Fermat primes. It is conjectured that a(n) is asymptotic to 0.00103368*li(10^n). LINKS Table of n, a(n) for n=1..7. Yves Gallot, Status of the smallest base values yielding Generalized Fermat primes Yves Gallot, How many prime numbers appear in a sequence ? Yves Gallot, A Problem on the Conjecture Concerning the Distribution of Generalized Fermat Prime numbers (a new method for the search for large primes) Mersenne Wiki, Table of known GF primes b^n+1 where n (exponent) is at least 8192 EXAMPLE a(5) = 3 because the generalized Fermat numbers F_13(b) where b<10^5 are prime only for b = 30406, 71852, 85654. PROG (PARI) a(n) = sum(b=1, 10^n/2-1, isprime((2*b)^8192+1)) CROSSREFS Cf. A215047, A215048, A215049, A215050, A215051, A215057, A215058, A215698, A215699, A215700. Sequence in context: A121981 A337413 A337409 * A231780 A093183 A278380 Adjacent sequences: A215958 A215959 A215960 * A215962 A215963 A215964 KEYWORD nonn,more AUTHOR Henryk Dabrowski, Aug 29 2012 STATUS approved

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Last modified September 11 06:27 EDT 2024. Contains 375814 sequences. (Running on oeis4.)