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A093402 Primes of the form 40*R_n + 9, where R_n is the repunit (A002275) of length n. 2
449, 44449, 444449, 444444444444444444444444444444444444444444444449, 444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444449 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes of the form (4*10^n + 41)/9. - Vincenzo Librandi, Nov 16 2010

LINKS

Table of n, a(n) for n=1..5.

Makoto Kamada, Prime numbers of the form 44...449.

Index entries for primes involving repunits

MATHEMATICA

Select[Table[FromDigits[PadLeft[{9}, n, 4]], {n, 120}], PrimeQ] (* Harvey P. Dale, May 21 2011 *)

CROSSREFS

Cf. A056683 (corresponding n).

Sequence in context: A036945 A201182 A012169 * A012062 A079659 A304511

Adjacent sequences:  A093399 A093400 A093401 * A093403 A093404 A093405

KEYWORD

nonn

AUTHOR

Rick L. Shepherd, Mar 28 2004

STATUS

approved

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Last modified April 8 22:35 EDT 2020. Contains 333331 sequences. (Running on oeis4.)