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 A290877 Numbers k such that 3*10^k + 59 is prime. 0
 1, 2, 4, 7, 18, 19, 22, 26, 36, 46, 49, 64, 82, 121, 1204, 1716, 2359, 4541, 7194, 8095, 14857, 18596, 27648, 37066, 109861, 171391 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS For k > 1, numbers such that the digit 3 followed by k-2 occurrences of the digit 0 followed by the digits 59 is prime (see Example section). a(27) > 2*10^5. LINKS Table of n, a(n) for n=1..26. Makoto Kamada, Factorization of near-repdigit-related numbers. Makoto Kamada, Search for 30w59. EXAMPLE 4 is in this sequence because 3*10^4 + 59 = 30059 is prime. Initial terms and primes associated: a(1) = 1, 89; a(2) = 2, 359; a(3) = 4, 30059; a(4) = 7; 30000059; a(5) = 18, 3000000000000000059; etc. MATHEMATICA Select[Range[0, 100000], PrimeQ[3*10^# + 59] &] PROG (PARI) isok(k) = ispseudoprime(3*10^k + 59) \\ Altug Alkan, Aug 13 2017 CROSSREFS Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269. Sequence in context: A342538 A076894 A047871 * A103032 A215649 A259351 Adjacent sequences: A290874 A290875 A290876 * A290878 A290879 A290880 KEYWORD nonn,more,hard AUTHOR Robert Price, Aug 13 2017 EXTENSIONS a(25)-a(26) from Robert Price, Aug 25 2018 STATUS approved

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Last modified December 8 07:12 EST 2023. Contains 367662 sequences. (Running on oeis4.)