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A102374 Numbers k such that k77777 is prime. 0
24, 32, 39, 50, 54, 66, 74, 75, 78, 83, 90, 99, 101, 108, 110, 114, 135, 143, 152, 159, 167, 173, 186, 188, 204, 206, 207, 209, 219, 221, 230, 233, 236, 242, 248, 251, 255, 261, 263, 264, 276, 279, 284, 285, 321, 338, 341, 356, 362, 372, 374, 380, 393, 401, 404, 422, 426, 428, 431, 437, 461 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..61.

EXAMPLE

If k=24, then k77777 = 2477777 (prime).

If k=66, then k77777 = 6677777 (prime).

If k=99, then k77777 = 9977777 (prime).

PROG

(MAGMA) [ n: n in [1..700] | IsPrime(Seqint([7, 7, 7, 7, 7] cat Intseq(n))) ]; // Vincenzo Librandi, Feb 04 2011

CROSSREFS

Sequence in context: A064673 A034782 A289554 * A317534 A240068 A269424

Adjacent sequences:  A102371 A102372 A102373 * A102375 A102376 A102377

KEYWORD

base,nonn

AUTHOR

Parthasarathy Nambi, Feb 22 2005

STATUS

approved

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Last modified October 20 04:37 EDT 2018. Contains 316378 sequences. (Running on oeis4.)