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A124643 Primes of the form p = k*10^m - 1 where k is 3, 6 or 9, such that p+2 is also a prime. 0
29, 59, 599, 2999, 8999, 29999999 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

There are no more terms for m <= 34936. - Herman Jamke (hermanjamke(AT)fastmail.fm), Apr 29 2007

LINKS

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

M. Kamada, Factorizations of near-repdigit numbers

EXAMPLE

a(1)= because 3*10^1-1 = 29 and 3*10^1+1 = 31 are primes.

a(2)= because 6*10^1-1 = 59 and 6*10^1+1 = 61 are primes.

a(3)= because 6*10^2-1 = 599 and 6*10^2+1 = 601 are primes.

a(4)= because 3*10^3-1 = 2999 and 3*10^3+1 = 3001 are primes.

a(5)= because 9*10^3-1 = 8999 and 9*10^3+1 = 9001 are primes.

a(6)= because 3*10^7-1 = 29999999 and 3*10^7+1 = 30000001 are primes.

CROSSREFS

Sequence in context: A078948 A269263 A042676 * A042678 A042680 A286005

Adjacent sequences:  A124640 A124641 A124642 * A124644 A124645 A124646

KEYWORD

more,nonn

AUTHOR

Lekraj Beedassy, Dec 21 2006

EXTENSIONS

Edited by N. J. A. Sloane, Jan 01 2007

STATUS

approved

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Last modified February 23 02:29 EST 2019. Contains 320411 sequences. (Running on oeis4.)