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 A064118 Numbers n such that the first n digits of e form a prime. 12
 1, 3, 7, 85, 1781, 2780, 112280, 155025 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The primes are given in A007512. Sequences A065815, A119344, A136583, A210706,... are analogs for gamma, sqrt(3), sqrt(10), 3^(1/3),.... The MathWorld page about "Constant Primes" lists further examples. - M. F. Hasler, Aug 31 2013 REFERENCES C. A. Pickover, The Mathematics of Oz, "2, 271, 2718281", Chapter 95, Camb.Univ.Press, UK 2002. LINKS Eric Weisstein's World of Mathematics, Constant Primes Eric Weisstein's World of Mathematics, e Digits Eric Weisstein's World of Mathematics, e-Prime Eric Weisstein's World of Mathematics, Integer Sequence Primes EXAMPLE a(2)=3 because 271 is prime. MATHEMATICA Do[If[PrimeQ[FromDigits[RealDigits[N[E, n + 10], 10, n][[1]]]], Print[n]], {n, 1, 2300}] CROSSREFS Cf. A001113. Cf. A047658. Sequence in context: A219588 A219375 A326427 * A041705 A137130 A058379 Adjacent sequences:  A064115 A064116 A064117 * A064119 A064120 A064121 KEYWORD base,more,nonn AUTHOR Shyam Sunder Gupta, Sep 09 2001 EXTENSIONS One more term from Robert G. Wilson v, Sep 28 2001 a(6) from Eric W. Weisstein, Jan 17 2005 a(7) from Eric W. Weisstein, Jul 03 2009 a(8) from Eric W. Weisstein, Oct 11 2010 STATUS approved

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Last modified February 16 21:46 EST 2020. Contains 331975 sequences. (Running on oeis4.)