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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
OFFSET
1,3
EXAMPLE
a(3) = 32 because there are 32 primes in the set, from p(129)=727 to p(962)=7577.
CROSSREFS
Sequence in context: A318022 A320407 A189651 * A125369 A126527 A265842
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