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A283448 Numbers k such that (265*10^k + 11)/3 is prime. 0
1, 2, 3, 5, 14, 18, 38, 65, 217, 218, 342, 560, 648, 962, 1151, 2043, 2113, 2641, 5738, 13295, 15793, 20424, 35729, 48474, 62298, 88077 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
For k>1, numbers such that the digits 88 followed by k-1 occurrences of the digit 3 followed by the digit 7 is prime (see Example section).
a(27) > 2*10^5.
LINKS
Makoto Kamada, Search for 883w7.
EXAMPLE
3 is in this sequence because (265*10^3 + 11)/3 = 88337 is prime.
Initial terms and primes associated:
a(1) = 1, 887;
a(2) = 2, 8837;
a(3) = 3, 88337;
a(4) = 5, 8833337;
a(5) = 14, 8833333333333337; etc.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[(265*10^# + 11)/3] &]
PROG
(PARI) isok(n) = isprime((265*10^n + 11)/3); \\ Indranil Ghosh, Mar 09 2017
CROSSREFS
Sequence in context: A233082 A039575 A291923 * A177901 A143743 A336273
KEYWORD
nonn,more,hard
AUTHOR
Robert Price, Mar 07 2017
STATUS
approved

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)