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A108334
Numbers k such that the string 10197k is prime.
1
7, 13, 17, 23, 29, 31, 41, 47, 71, 83, 101, 107, 137, 157, 169, 193, 197, 217, 221, 223, 259, 301, 347, 373, 389, 391, 403, 427, 437, 469, 491, 497, 511, 527, 559, 563, 581, 587, 613, 631, 653, 673, 679, 683, 689, 701, 703, 727, 743, 749, 757, 799, 827, 833, 857, 893, 899, 907, 917
OFFSET
1,1
COMMENTS
101 and 97 are primes.
LINKS
EXAMPLE
k=7 and k=83 are in the sequence because 10197k = 101977 and 10197k = 1019783 are prime.
MATHEMATICA
Select[Range[10^3], PrimeQ[10197*10^IntegerLength[#] + #] &] (* Michael De Vlieger, Jan 22 2018 *)
PROG
(Magma) [ n: n in [1..1750] | IsPrime(Seqint(Intseq(n) cat [7, 9, 1, 0, 1])) ]; // Vincenzo Librandi, Feb 02 2011
CROSSREFS
Sequence in context: A226138 A180263 A002733 * A288713 A136083 A167276
KEYWORD
nonn,base
AUTHOR
Parthasarathy Nambi, Jun 30 2005
STATUS
approved