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 A183177 Numbers n such that (10^(2n+1)+15*10^n-1)/3 is prime. 2
 1, 7, 85, 94, 273, 356, 1077, 1797, 6758, 30232 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(11) > 10^5. - Robert Price, Apr 21 2016 REFERENCES C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9. LINKS Patrick De Geest, World!Of Numbers, Palindromic Wing Primes (PWP's) Makoto Kamada, Prime numbers of the form 33...33833...33 FORMULA a(n) = (A077792(n)-1)/2. MATHEMATICA Do[If[PrimeQ[(10^(2n + 1) + 15*10^n - 1)/3], Print[n]], {n, 3000}] PROG (PARI) is(n)=ispseudoprime((10^(2*n+1)+15*10^n-1)/3) \\ Charles R Greathouse IV, Jun 13 2017 CROSSREFS Cf. A004023, A077775-A077798, A107123-A107127, A107648, A107649, A115073, A183174-A183187. Sequence in context: A172455 A258174 A254569 * A058795 A027459 A329108 Adjacent sequences: A183174 A183175 A183176 * A183178 A183179 A183180 KEYWORD nonn,more,base AUTHOR Ray Chandler, Dec 28 2010 EXTENSIONS a(10) from Robert Price, Apr 21 2016 STATUS approved

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Last modified March 26 02:09 EDT 2023. Contains 361529 sequences. (Running on oeis4.)