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A103862
Numbers n such that the string 10000n is the decimal expansion of a prime number.
1
3, 33, 37, 39, 81, 99, 103, 121, 139, 141, 169, 189, 223, 229, 247, 253, 261, 271, 303, 339, 349, 357, 363, 379, 439, 451, 453, 457, 481, 511, 537, 583, 591, 609, 643, 651, 657, 667, 687, 691, 721, 723, 733, 741, 747, 759, 763, 769, 789, 799, 813, 819, 831
OFFSET
1,1
COMMENTS
All terms == 1 or 3 (mod 6). - Robert Israel, Mar 27 2018
LINKS
EXAMPLE
3 is in the sequence because 100003 is prime.
81 is in the sequence because 1000081 is prime.
247 is in the sequence because 10000247 is prime.
MAPLE
select(n -> isprime(n+10^(ilog10(n)+5)), [seq(seq(6*i+j, j=[1, 3]), i=0..1000)]); # Robert Israel, Mar 27 2018
MATHEMATICA
Select[Range[1000], PrimeQ[10000*10^IntegerLength[#]+#]&] (* Harvey P. Dale, Jun 30 2020 *)
PROG
(Magma) [ n: n in [1..900] | IsPrime(Seqint(Intseq(n) cat [0, 0, 0, 0, 1])) ]; // Klaus Brockhaus, Feb 02 2011
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Parthasarathy Nambi, Mar 30 2005
STATUS
approved