A110055 Numbers n such that the string 333n is the decimal expansion of a prime number.

1, 11, 17, 29, 31, 43, 47, 49, 53, 59, 77, 91, 101, 103, 107, 131, 139, 161, 187, 197, 209, 227, 233, 253, 269, 271, 283, 287, 299, 323, 331, 337, 341, 349, 367, 383, 397, 419, 427, 433, 439, 449, 451, 457, 479, 491, 493, 497, 503, 517, 533, 539, 563, 581

Offset

1,2

Links

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

Example

1 is in the sequence because 3331 is prime.
59 is in the sequence because 33359 is prime.
107 is in the sequence because 333107 is prime.

Mathematica

Select[Range[1000], PrimeQ[FromDigits[Join[{3, 3, 3}, IntegerDigits[ # ]]]] &] (Delarte)
Select[Range[1000], PrimeQ[333*10^IntegerLength[#]+#]&] (* Harvey P. Dale, Jun 03 2023 *)

Prog

(Magma) [ n: n in [1..600] | IsPrime(Seqint(Intseq(n) cat [3, 3, 3])) ]; // Klaus Brockhaus, Feb 03 2011

Crossrefs

Sequence in context: A079367 A120139 A191061 * A240095 A105886 A225493

Adjacent sequences: A110052 A110053 A110054 * A110056 A110057 A110058

Keyword

nonn,base

Author

Parthasarathy Nambi, Sep 04 2005

Extensions

More terms from Alonso del Arte, Sep 06 2005

Status

approved