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 A215058 Number of primes of the form 1 + b^128 for 1 < b < 10^n. 11
 0, 0, 7, 25, 242, 1933, 16080, 139921, 1234958 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Primes 1 + b^128 are a form of generalized Fermat primes. It is conjectured that a(n) is asymptotic to 0.0242888*li(10^n) LINKS Yves Gallot, How many prime numbers appear in a sequence ? EXAMPLE a(3) = 7 because the generalized Fermat numbers F_7(b) where b<10^3 are prime only for b: 120, 190, 234, 506, 532, 548, 960. PROG (PARI) a(n) = sum(b=1, 10^n/2-1, isprime((2*b)^128+1)) CROSSREFS Cf. A215047, A215048, A215049, A215050, A215051, A215057. Sequence in context: A293532 A208823 A197913 * A214538 A290882 A197651 Adjacent sequences:  A215055 A215056 A215057 * A215059 A215060 A215061 KEYWORD nonn,more AUTHOR Henryk Dabrowski, Aug 01 2012 EXTENSIONS a(8)-a(9) from Kellen Shenton, Aug 10 2020 STATUS approved

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Last modified June 22 10:56 EDT 2021. Contains 345375 sequences. (Running on oeis4.)