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A020467 Primes that contain digits 5 and 7 only. 8
5, 7, 557, 577, 757, 5557, 7577, 7757, 57557, 75557, 75577, 77557, 555557, 575557, 575777, 577757, 757577, 775757, 775777, 5555777, 5557757, 5575777, 5577577, 5755577, 5775557, 5777557, 7575577, 7577777, 55555777, 55575757, 55755757 (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[{5, 7}, n], PrimeQ], {n, 8}]]

PROG

(MAGMA) [p: p in PrimesUpTo(55755757 ) | Set(Intseq(p)) subset [5, 7]]; // Vincenzo Librandi, Jul 27 2012

CROSSREFS

Sequence in context: A114368 A260830 A260827 * A089344 A114363 A083687

Adjacent sequences:  A020464 A020465 A020466 * A020468 A020469 A020470

KEYWORD

nonn,base

AUTHOR

David W. Wilson

STATUS

approved

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Last modified May 30 00:42 EDT 2017. Contains 287304 sequences.