A109304 Numbers n such that string reversal of n is a substring of n-th prime.

7, 94, 281, 886, 16638, 60757, 642469, 689301, 784911, 3631421, 7144652, 7967301, 9428958, 17741923, 75060705, 141521639, 1060975242, 3087218304, 32644390236, 43670299761

Offset

1,1

Comments

a(21) > pi(2*10^12). [From Donovan Johnson, May 08 2010]

Links

Table of n, a(n) for n=1..20.

Example

94th prime, 491, contains 49 = the string reversal of its index;
281st prime, 1823, contains 182 = the string reversal of its index;
7144652nd prime, 125644177, contains 2564417 = the string reversal of its index; etc.

Mathematica

fQ[n_] := StringPosition[ ToString[ Prime[n]], StringReverse[ ToString[n]]] != {}; Do[ If[ fQ[n], Print[n]], {n, 107350907, 2 10^9}] (* Robert G. Wilson v, Jun 28 2005 *)

Crossrefs

Corresponding primes form A109305.

Sequence in context: A218835 A219417 A220405 * A134113 A071584 A132114

Adjacent sequences: A109301 A109302 A109303 * A109305 A109306 A109307

Keyword

base,nonn

Author

Zak Seidov, Jun 25 2005

Extensions

a(14)-a(16) from Robert G. Wilson v, Jun 28 2005

a(17)-a(20) from Donovan Johnson, May 08 2010

Status

approved