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1, 2, 3, 9, 17, 18, 20, 24, 29, 36, 48, 114, 126, 135, 153, 170, 241, 363, 483, 579, 681, 948, 2483, 2798, 3081, 5137, 5640, 6890, 7080, 12600, 16929, 24253, 24793, 35546, 52956, 69645, 133831, 206688
a(3839) > 23*10^5.
a(38) from Robert Price, Jul 25 2024
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For k > 1, numbers k such that the digit 3 followed by k-2 occurrences of the digit 6 followed by the digits 73 is prime (see Example section).
Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/primedifficultyprime_difficulty.txt">Search for 36w73.</a>.
Initial terms and primes associated primes:
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Makoto Kamada, <a href="httphttps://stdkmd.comnet/nrr/prime/primedifficulty.txt">Search for 36w73.</a>
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Numbers n k such that (11*10^nk + 19)/3 is prime.
1, 2, 3, 9, 17, 18, 20, 24, 29, 36, 48, 114, 126, 135, 153, 170, 241, 363, 483, 579, 681, 948, 2483, 2798, 3081, 5137, 5640, 6890, 7080, 12600, 16929, 24253, 24793, 35546, 52956, 69645, 133831
For nk>1, numbers such that the digit 3 followed by nk-2 occurrences of the digit 6 followed by the digits 73 is prime (see Example section).
a(3738) > 2*10^5.
3 is in this sequence because (11*10^n3 + 19)/3 = 3673 is prime.
Select[Range[0, 100000], PrimeQ[(11*10^# + 19)/3] &]
(PARI) is(n)=isprime((11*10^n + 19)/3) \\ Charles R Greathouse IV, Mar 16 2016
a(37) from Robert Price, Sep 16 2018
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