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A108112 Numbers k such that the string 3129k is prime. 1
29, 31, 37, 41, 43, 67, 71, 79, 89, 103, 121, 169, 193, 199, 209, 221, 223, 253, 257, 263, 271, 289, 323, 383, 391, 421, 431, 439, 443, 461, 463, 487, 517, 521, 523, 557, 559, 601, 611, 613, 617, 619, 629, 641, 677, 689, 691, 701, 733, 757, 769, 781, 787, 799, 803, 811, 821, 827, 839, 859 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

k=29 is in the sequence because 3129k = 312929 is prime.

k=103 is in the sequence because 3129k = 3129103 is prime.

MATHEMATICA

Select[Range[1000], PrimeQ[3129*10^IntegerLength[#]+#]&] (* Harvey P. Dale, Jan 14 2015 *)

PROG

(MAGMA) [ n: n in [1..1750] | IsPrime(Seqint(Intseq(n) cat [9, 2, 1, 3])) ]; // Vincenzo Librandi, Feb 02 2011

CROSSREFS

Sequence in context: A157498 A031062 A054056 * A007641 A050656 A050667

Adjacent sequences:  A108109 A108110 A108111 * A108113 A108114 A108115

KEYWORD

nonn,base

AUTHOR

Parthasarathy Nambi, Jun 25 2005

STATUS

approved

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Last modified October 22 18:45 EDT 2021. Contains 348175 sequences. (Running on oeis4.)