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A295522 Numbers k such that (16*10^k + 107)/3 is prime. 0
0, 1, 2, 8, 18, 24, 96, 152, 204, 296, 566, 703, 1814, 4342, 4626, 5412, 6704, 6752, 7096, 27004, 37976, 173251 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
For k > 1, numbers k such that the digit 5 followed by k-2 occurrences of the digit 3 followed by the digits 69 is prime (see Example section).
a(23) > 2*10^5.
LINKS
Makoto Kamada, Search for 53w69.
EXAMPLE
2 is in this sequence because (16*10^2 + 107)/3 = 569 is prime.
Initial terms and associated primes:
a(1) = 0, 41;
a(2) = 1, 89;
a(3) = 2, 569;
a(4) = 8, 533333369;
a(5) = 18, 5333333333333333369; etc.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[(16*10^# + 107)/3] &]
CROSSREFS
Sequence in context: A338140 A306394 A109136 * A065131 A192157 A268810
KEYWORD
nonn,more,hard
AUTHOR
Robert Price, Nov 28 2017
EXTENSIONS
a(22) from Robert Price, Mar 06 2019
STATUS
approved

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Last modified July 21 09:38 EDT 2024. Contains 374472 sequences. (Running on oeis4.)