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 A068104 Smallest prime starting with n 3s. 17
 2, 3, 331, 3331, 33331, 333331, 3333331, 33333331, 3333333319, 33333333329, 333333333323, 3333333333301, 33333333333319, 333333333333307, 3333333333333301, 33333333333333323, 333333333333333331 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS MATHEMATICA Join[{2, 3}, Table[SelectFirst[Join[10FromDigits[PadRight[{}, k, 3]]+{1, 7, 9}, Flatten[Table[100 FromDigits[PadRight[{}, k, 3]]+10n+{1, 3, 7, 9}, {n, 0, 9}]], Flatten[Table[1000 FromDigits[PadRight[{}, k, 3]]+100n+{1, 3, 7, 9}, {n, 0, 99}]]], PrimeQ], {k, 2, 20}]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 01 2019 *) CROSSREFS Cf. A065584, A068103, A068105. Sequence in context: A004876 A307212 A177505 * A065586 A110931 A097654 Adjacent sequences:  A068101 A068102 A068103 * A068105 A068106 A068107 KEYWORD base,easy,nonn AUTHOR Amarnath Murthy, Feb 20 2002 EXTENSIONS More terms from Sascha Kurz, Mar 19 2002 STATUS approved

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Last modified January 29 01:40 EST 2020. Contains 331328 sequences. (Running on oeis4.)