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 A295396 Numbers k such that 3*10^k + 11 is prime. 0
 1, 2, 3, 4, 13, 17, 27, 29, 40, 99, 107, 155, 165, 207, 230, 328, 723, 3854, 20929, 65247, 85703, 101065, 186019 (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 11 is prime (see Example section). a(24) > 2*10^5. LINKS Makoto Kamada, Factorization of near-repdigit-related numbers. Makoto Kamada, Search for 30w11 EXAMPLE 2 is in this sequence because 3*10^2 + 11 = 311 is prime. Initial terms and primes associated: a(1) = 1, 41; a(2) = 2, 311; a(3) = 3, 3011; a(4) = 4, 30011; a(5) = 13, 30000000000011; etc. MATHEMATICA Select[Range[0, 100000], PrimeQ[3*10^# + 11] &] PROG (PARI) isok(k) = isprime(3*10^k + 11); \\ Michel Marcus, Nov 22 2017 CROSSREFS Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269. Sequence in context: A126129 A102947 A281512 * A236440 A162222 A010346 Adjacent sequences:  A295393 A295394 A295395 * A295397 A295398 A295399 KEYWORD nonn,more,hard AUTHOR Robert Price, Nov 21 2017 EXTENSIONS a(22)-a(23) from Robert Price, Jul 22 2018 STATUS approved

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Last modified October 15 00:14 EDT 2019. Contains 328025 sequences. (Running on oeis4.)