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 A109304 Numbers n such that string reversal of n is a substring of n-th prime. 3

%I

%S 7,94,281,886,16638,60757,642469,689301,784911,3631421,7144652,

%T 7967301,9428958,17741923,75060705,141521639,1060975242,3087218304,

%U 32644390236,43670299761

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

%C a(21) > pi(2*10^12). [From _Donovan Johnson_, May 08 2010]

%e 94th prime, 491, contains 49 = the string reversal of its index;

%e 281st prime, 1823, contains 182 = the string reversal of its index;

%e 7144652nd prime, 125644177, contains 2564417 = the string reversal of its index; etc.

%t 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 *)

%Y Corresponding primes form A109305.

%K base,nonn

%O 1,1

%A _Zak Seidov_, Jun 25 2005

%E a(14)-a(16) from _Robert G. Wilson v_, Jun 28 2005

%E a(17)-a(20) from _Donovan Johnson_, May 08 2010

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Last modified March 31 21:40 EDT 2023. Contains 361673 sequences. (Running on oeis4.)