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 A093633 Primes of the form 8*10^k + R_k, where R_k is the repunit (A002275) of length k. 1
 811, 8111, 811111111111111111111111111, 811111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111, 8111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The next term (a(6)) has 475 digits. - Harvey P. Dale, Sep 16 2016 LINKS Table of n, a(n) for n=1..5. Makoto Kamada, Prime numbers of the form 811...11. Index entries for primes involving repunits MATHEMATICA Select[Table[FromDigits[PadRight[{8}, n, 1]], {n, 150}], PrimeQ] (* Harvey P. Dale, Sep 16 2016 *) CROSSREFS Cf. A002275, A056722 (corresponding k). Sequence in context: A068278 A208189 A183216 * A045228 A252223 A158667 Adjacent sequences: A093630 A093631 A093632 * A093634 A093635 A093636 KEYWORD nonn AUTHOR Rick L. Shepherd, Apr 06 2004 STATUS approved

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Last modified November 30 12:38 EST 2023. Contains 367461 sequences. (Running on oeis4.)