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 A061119 Primes in the sequence n^2 + 2^n (A001580). 9
 3, 17, 593, 32993, 2097593, 8589935681 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS p and p^2 + 2^p are both prime only for p=3. All positive n satisfy the congruence n=3 (mod 6). - Lekraj Beedassy, Sep 07 2004 For values of n, see A064539. - Lekraj Beedassy, Jan 01 2007 The next term has 605 digits. - Harvey P. Dale, Jul 19 2017 REFERENCES J.-M. De Koninck & A. Mercier, 1001 Problemes en Theorie Classique Des Nombres,Problem 165 pp. 30; 160, Ellipses Paris 2004. LINKS EXAMPLE a(3) = 593 = 2^9 +9^2. a(4) = 32993= 2^15 + 15^2. MATHEMATICA Select[Table[n^2+2^n, {n, 1000}], PrimeQ] (* Harvey P. Dale, Jul 19 2017 *) PROG (PARI) for(n=1, 10^7, if(isprime(n^2+2^n), print(n^2+2^n))) CROSSREFS Subsequence of A094133. Cf. A001580, A075896. Sequence in context: A128300 A292082 A001601 * A094133 A049985 A126579 Adjacent sequences:  A061116 A061117 A061118 * A061120 A061121 A061122 KEYWORD nonn AUTHOR Amarnath Murthy, Apr 21 2001 EXTENSIONS More terms from Jason Earls, Aug 09 2001. Next term too large to include. STATUS approved

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Last modified October 17 08:36 EDT 2019. Contains 328107 sequences. (Running on oeis4.)