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 A145711 Number of primes p in the range 9 < p <= prime(10^n) that have most significant and least significant decimal digit both equal to 7. 4
 0, 0, 32, 264, 2103, 17891, 155956, 1379175, 12374435, 112213301 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS EXAMPLE a(3) = 32 because there are 32 primes in the set, from p(129)=727 to p(962)=7577. CROSSREFS Cf. A145709 - A145713. Sequence in context: A318022 A320407 A189651 * A125369 A126527 A265842 Adjacent sequences: A145708 A145709 A145710 * A145712 A145713 A145714 KEYWORD base,hard,nonn AUTHOR Enoch Haga, Oct 16 2008 EXTENSIONS Edited by N. J. A. Sloane, Aug 16 2010, based on emails from Charles R Greathouse IV, Alois P. Heinz, R. J. Mathar and Jack Brennen (who computed a(6)). Offset changed to agree with A145713 by D. S. McNeil, Aug 29 2010 a(9), a(10) from D. S. McNeil, Aug 29 2010 STATUS approved

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Last modified December 3 00:23 EST 2022. Contains 358510 sequences. (Running on oeis4.)