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A020457 Primes that contain digits 1 and 9 only. 7
11, 19, 191, 199, 911, 919, 991, 1999, 9199, 11119, 19919, 19991, 91199, 99119, 99191, 99991, 111119, 111191, 111919, 119191, 191119, 191911, 191999, 199999, 911111, 919111, 991999, 999199, 1111991, 1191119, 1191191, 1191199, 1191991, 1199999 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Flatten[Table[Select[FromDigits/@Tuples[{1, 9}, n], PrimeQ], {n, 7}]] (* Vincenzo Librandi, Jul 27 2012 *)

PROG

(MAGMA) [p: p in PrimesUpTo(1199999) | Set(Intseq(p)) subset [1, 9]]; // Vincenzo Librandi, Jul 27 2012

CROSSREFS

Sequence in context: A089773 A048389 A163151 * A032370 A129908 A129909

Adjacent sequences:  A020454 A020455 A020456 * A020458 A020459 A020460

KEYWORD

nonn,base

AUTHOR

David W. Wilson

STATUS

approved

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Last modified July 25 14:27 EDT 2017. Contains 289795 sequences.