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 A273063 Numbers k such that (112*10^k + 17)/3 is prime. 0
 0, 1, 2, 3, 4, 8, 44, 53, 79, 89, 95, 120, 224, 259, 290, 488, 725, 821, 1815, 3096, 3100, 3404, 5909, 8054, 11879, 17298, 25588, 41516, 127324, 191900 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS For k>0, numbers k such that the digits 37 followed by k-1 occurrences of the digit 3 followed by the digit 9 is prime (see Example section). a(31) > 2*10^5. LINKS Makoto Kamada, Factorization of near-repdigit-related numbers. Makoto Kamada, Search for 373w9. EXAMPLE 3 is in this sequence because (112*10^3+17)/3 = 37339 is prime. Initial terms and primes associated: a(1) = 0, 43; a(2) = 1, 379: a(3) = 2, 3739; a(4) = 3, 37339; a(5) = 4, 373339, etc. MATHEMATICA Select[Range[0, 100000], PrimeQ[(112*10^# + 17)/3] &] PROG (PARI) is(n)=ispseudoprime((112*10^n + 17)/3) \\ Charles R Greathouse IV, Jun 13 2017 CROSSREFS Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269. Sequence in context: A100997 A128657 A105421 * A217353 A258194 A033554 Adjacent sequences:  A273060 A273061 A273062 * A273064 A273065 A273066 KEYWORD nonn,more AUTHOR Robert Price, May 14 2016 EXTENSIONS a(29)-a(30) from Robert Price, Mar 05 2020 STATUS approved

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Last modified June 20 08:43 EDT 2021. Contains 345162 sequences. (Running on oeis4.)