A093400 - OEIS

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A093400

Primes of the form 10*R_k + 9, where R_k is the repunit (A002275) of length k.

1

19, 11119, 111119, 11111119, 11111111111111119, 11111111111111111111111111111111111111111111111119

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OFFSET

1,1

COMMENTS

The next term has 684 digits. - Harvey P. Dale, Dec 11 2013

LINKS

Table of n, a(n) for n=1..6.

Makoto Kamada, Prime numbers of the form 11...119.

Index entries for primes involving repunits

MATHEMATICA

Select[Table[FromDigits[PadLeft[{9}, n, 1]], {n, 1000}], PrimeQ] (* Harvey P. Dale, Dec 11 2013 *)

CROSSREFS

Cf. A056659 (corresponding k and count of digits 1 in a(n)).

Sequence in context: A270972 A260005 A276739 * A265169 A174306 A270069

Adjacent sequences: A093397 A093398 A093399 * A093401 A093402 A093403

KEYWORD

nonn

AUTHOR

Rick L. Shepherd, Mar 28 2004

STATUS

approved