

A056803


Numbers n such that 12 repeated n times followed by 1 is a palindromic prime.


3




OFFSET

1,1


LINKS

Table of n, a(n) for n=1..10.
P. De Geest, SUPP Reference Table


EXAMPLE

12121212121 is prime so 5 appears in the sequence.


MATHEMATICA

Do[m = n; If[PrimeQ[120(10^(2n)  1)/99 + 1], Print[n]], {n, 1, 600}]


CROSSREFS

Corresponding primes are given in A092696. Corresponding decimal digit lengths are given in A062209. a(k) = (A062209(k1)1)/2.
Sequence in context: A266203 A264683 A286033 * A071706 A196418 A189560
Adjacent sequences: A056800 A056801 A056802 * A056804 A056805 A056806


KEYWORD

nonn,base


AUTHOR

Robert G. Wilson v, Aug 22 2000


EXTENSIONS

More terms from Rick L. Shepherd, Mar 04 2004


STATUS

approved



