A102503 Primes of the concatenated form 9nn9.

910109, 913139, 916169, 917179, 920209, 923239, 928289, 931319, 935359, 937379, 946469, 953539, 956569, 961619, 965659, 968689, 974749, 982829, 994949, 995959, 998989, 9101010109, 9101310139, 9101810189, 9104210429, 9104810489

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..2500

Example

910109 is prime and of the form 9nn9 for n=10.
9101310139 is prime and of the form 9nn9 for n=1013.

Mathematica

Select[Table[FromDigits[Join[{9}, IntegerDigits[n], IntegerDigits[n], {9}]], {n, 1100}], PrimeQ] (* Harvey P. Dale, Jul 28 2020 *)

Crossrefs

Cf. A102484 for sequence of all numbers of form 9nn9. A102502 for the n values corresponding to the primes in this sequence.

Sequence in context: A015333 A141461 A035793 * A251908 A186608 A236617

Adjacent sequences: A102500 A102501 A102502 * A102504 A102505 A102506

Keyword

easy,nonn,base

Author

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

Status

approved