A103853 - OEIS

A103853

Numbers n such that the string 1000n is the decimal expansion of a prime number.

7, 9, 19, 43, 49, 57, 69, 117, 121, 133, 151, 159, 171, 183, 187, 193, 199, 211, 213, 231, 249, 253, 273, 289, 291, 303, 313, 333, 357, 367, 381, 393, 397, 403, 409, 423, 427, 429, 453, 457, 507, 537, 541, 547, 577, 579, 589, 609, 619, 621, 639, 651, 667

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OFFSET

1,1

LINKS

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

EXAMPLE

7 is in the sequence because 10007 is prime.

49 is in the sequence because 100049 is prime.

187 is in the sequence because 1000187 is prime.

MATHEMATICA

Select[Range[700], PrimeQ[FromDigits[Join[{1, 0, 0, 0}, IntegerDigits[#]]]]&] (* Harvey P. Dale, Oct 03 2011 *)

PROG