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A108054 Integers n such that 10^n+49 is prime. 27
1, 2, 3, 5, 8, 17, 24, 32, 65, 66, 67, 79, 83, 98, 152, 260, 781, 1225, 1777, 2023, 2411, 3469, 5347, 10646, 11335, 13989, 14792, 16731, 19015, 29471, 39187, 41456, 80883 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "10049".

LINKS

Table of n, a(n) for n=1..33.

Makoto Kamada, List of near-repdigit-related prime numbers.

Index entries for primes involving repunits.

EXAMPLE

n = 8 ==> 10^8+49 = 100000049, which is prime.

MATHEMATICA

a={}; Do[p=10^n+49; If[PrimeQ[p], AppendTo[a, n]], {n, 0, 10^3, 1}]; a (* Vladimir Joseph Stephan Orlovsky, Jul 17 2008 *)

PROG

(PARI) for(n=1, 1e4, if(ispseudoprime(10^n+49), print1(n", "))) \\ Charles R Greathouse IV, Jul 25 2011

CROSSREFS

Cf. A049054, A088274, A088275, A095688.

Sequence in context: A030034 A093000 A122630 * A123612 A077177 A145793

Adjacent sequences:  A108051 A108052 A108053 * A108055 A108056 A108057

KEYWORD

more,nonn

AUTHOR

Julien Peter Benney (jpbenney(AT)ftml.net), Jun 02 2005

EXTENSIONS

a(23) from Ray G. Opao, Dec 13 2006

a(24)-a(31) from Robert Price, May 28 2010

Edited by Ray Chandler, Dec 23 2010

a(32) from Robert Price, Dec 27 2010

a(33) from Robert Price, Mar 03 2011

STATUS

approved

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Last modified September 26 05:09 EDT 2017. Contains 292502 sequences.