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A093174 Primes of the form 40*R_n + 1, where R_n is the repunit (A002275) of length n. 5
41, 4441, 44444444441, 4444444444444444444444444441, 4444444444444444444444444444444444444444444444444444441, 4444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444441 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes of the form (4*10^n - 31)/9. - Vincenzo Librandi, Nov 16 2010

LINKS

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

Makoto Kamada, Prime numbers of the form 44...441.

Index entries for primes involving repunits

CROSSREFS

Cf. A056681 (corresponding n), A173768.

Sequence in context: A282054 A107690 A068815 * A280677 A209104 A233079

Adjacent sequences:  A093171 A093172 A093173 * A093175 A093176 A093177

KEYWORD

nonn

AUTHOR

Rick L. Shepherd, Mar 27 2004

EXTENSIONS

Edited by N. J. A. Sloane, Feb 26 2010

STATUS

approved

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Last modified March 26 12:27 EDT 2019. Contains 321497 sequences. (Running on oeis4.)