A103862 Numbers n such that the string 10000n is the decimal expansion of a prime number.

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

Robert Israel, Table of n, a(n) for n = 1..10000

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

Cf. A103601, A103602, A103603.

Sequence in context: A106413 A284064 A101968 * A180245 A084502 A248397

Adjacent sequences: A103859 A103860 A103861 * A103863 A103864 A103865

Keyword

base,nonn

Author

Parthasarathy Nambi, Mar 30 2005

Status

approved