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A294122
Numbers k such that 3*10^k + 37 is prime.
0
1, 2, 3, 7, 9, 15, 18, 23, 39, 147, 1104, 1158, 1466, 1514, 1935, 2149, 2203, 2553, 2730, 7169, 9807, 17684, 23828, 25824, 27207, 55679, 94964, 122977, 206927
OFFSET
1,2
COMMENTS
For k > 1, numbers k such that the digit 3 followed by k-2 occurrences of the digit 0 followed by the digits 37 is prime (see Example section).
a(30) > 3*10^5.
EXAMPLE
2 is in this sequence because 3*10^2 + 37 = 337 is prime.
Initial terms and associated primes:
a(1) = 1, 67;
a(2) = 2, 337;
a(3) = 3, 3037;
a(4) = 7, 30000037;
a(5) = 9, 3000000037; etc.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[3*10^# + 37] &]
KEYWORD
nonn,more,hard
AUTHOR
Robert Price, Oct 23 2017
EXTENSIONS
a(28) from Robert Price, Aug 15 2018
a(29) from Robert Price, Oct 26 2023
STATUS
approved