A102499 Primes of the concatenated form 3nn3.

313133, 323233, 328283, 329293, 338383, 343433, 349493, 350503, 352523, 356563, 364643, 367673, 380803, 383833, 392923, 394943, 395953, 397973, 3100010003, 3100310033, 3102410243, 3102510253, 3102810283, 3103910393, 3104610463

Offset

1,1

Links

Table of n, a(n) for n=1..25.

Example

313133 is prime and of the form 3nn3 for n=13.
3100010003 is prime and of the form 3nn3 for n=1000.

Mathematica

mn[n_]:=Module[{idn=IntegerDigits[n]}, FromDigits[Join[{3}, idn, idn, {3}]]]; Select[ mn/@ Range[ 1100], PrimeQ]  (* Harvey P. Dale, Feb 04 2011 *)

Crossrefs

Cf. A102896 for sequence of all numbers of form 3nn3. A102498 for the n values corresponding to the primes in this sequence.

Sequence in context: A250371 A210296 A214244 * A234121 A250152 A104826

Adjacent sequences: A102496 A102497 A102498 * A102500 A102501 A102502

Keyword

easy,nonn,base

Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Jan 13 2005

Status

approved