

A284741


Numbers k such that (29*10^k + 259)/9 is prime.


0



1, 3, 4, 6, 9, 10, 24, 27, 66, 76, 136, 346, 399, 978, 1228, 2227, 4005, 5916, 6394, 7438, 18934, 20020, 31866, 85438
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OFFSET

1,2


COMMENTS

For k>1, numbers such that the digit 3 followed by k2 occurrences of the digit 2 followed by the digits 51 is prime (see Example section).
a(25) > 10^5.


LINKS

Table of n, a(n) for n=1..24.
Makoto Kamada, Factorization of nearrepdigitrelated numbers.
Makoto Kamada, Search for 32w51.


EXAMPLE

3 is in this sequence because (29*10^3 + 259)/9 = 3251 is prime.
Initial terms and primes associated:
a(1) = 1, 61;
a(2) = 3, 3251;
a(3) = 4, 32251;
a(4) = 6, 3222251;
a(5) = 9, 3222222251; etc.


MATHEMATICA

Select[Range[0, 100000], PrimeQ[(29*10^# + 259)/9] &]


CROSSREFS

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.
Sequence in context: A268110 A124093 A025061 * A037969 A153236 A158705
Adjacent sequences: A284738 A284739 A284740 * A284742 A284743 A284744


KEYWORD

nonn,more,hard


AUTHOR

Robert Price, Apr 01 2017


STATUS

approved



