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A103603 Numbers k such that the string 101001000k is prime. 3
7, 29, 41, 79, 119, 137, 143, 169, 187, 241, 259, 263, 281, 307, 313, 319, 341, 361, 377, 403, 427, 439, 449, 461, 467, 493, 547, 553, 557, 587, 673, 689, 701, 703, 719, 721, 731, 781, 791, 847, 887, 901, 911, 931, 943, 979, 1027, 1073, 1093, 1097, 1103, 1207, 1219, 1229, 1307, 1327, 1331 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..57.

EXAMPLE

If k=7, then 101001000k = 1010010007 (prime).

If k=41, then 101001000k = 10100100041 (prime).

If k=119, then 101001000k = 101001000119 (prime).

MATHEMATICA

Select[Range[1500], PrimeQ[FromDigits[Join[{1, 0, 1, 0, 0, 1, 0, 0, 0}, IntegerDigits[ #]]]]&] (* Harvey P. Dale, Jul 12 2011 *)

PROG

(MAGMA) [ n: n in [1..1750] | IsPrime(Seqint(Intseq(n) cat [0, 0, 0, 1, 0, 0, 1, 0, 1])) ]; // Vincenzo Librandi, Feb 02 2011

CROSSREFS

Sequence in context: A155476 A166970 A075583 * A045465 A165492 A084201

Adjacent sequences:  A103600 A103601 A103602 * A103604 A103605 A103606

KEYWORD

base,nonn

AUTHOR

Parthasarathy Nambi, Mar 23 2005

STATUS

approved

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Last modified July 18 19:00 EDT 2019. Contains 325144 sequences. (Running on oeis4.)