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A082697 Numbers k such that (4*10^(k-1) - 7)/3 is a plateau prime. 25
3, 5, 7, 95, 161, 361, 1471, 2899, 3095, 3113, 15699, 17957, 42263, 111033 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Prime versus probable prime status and proofs are given in the author's table.

REFERENCES

C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.

LINKS

Table of n, a(n) for n=1..14.

Patrick De Geest, PDP Reference Table - 131.

Makoto Kamada, Prime numbers of the form 133...331.

Index entries for primes involving repunits.

FORMULA

a(n) = A056244(n+1) + 2.

EXAMPLE

k=7 -> (4*10^(7-1) - 7)/3 = 1333331.

CROSSREFS

Cf. A056244, A068645, A082698-A082720.

Sequence in context: A153138 A201270 A160360 * A051345 A242387 A104388

Adjacent sequences:  A082694 A082695 A082696 * A082698 A082699 A082700

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, Apr 13 2003

EXTENSIONS

a(13)=42263 from Patrick De Geest, Oct 03 2004

a(14)=111033 from Ray Chandler, Apr 14 2011

Edited by Ray Chandler, Nov 04 2014

STATUS

approved

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Last modified February 17 02:22 EST 2020. Contains 331976 sequences. (Running on oeis4.)