

A270339


Numbers k such that (11*10^k + 19)/3 is prime.


501



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
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OFFSET

1,2


COMMENTS

For k>1, numbers such that the digit 3 followed by k2 occurrences of the digit 6 followed by the digits 73 is prime (see Example section).
a(38) > 2*10^5.


LINKS

Table of n, a(n) for n=1..37.
Makoto Kamada, Search for 36w73.


EXAMPLE

3 is in this sequence because (11*10^3 + 19)/3 = 3673 is prime.
Initial terms and primes associated:
a(1) = 1, 43;
a(2) = 2, 373;
a(3) = 3, 3673;
a(4) = 9, 3666666673;
a(5) = 17, 366666666666666673, etc.


MATHEMATICA

Select[Range[0, 100000], PrimeQ[(11*10^# + 19)/3] &]


PROG

(PARI) is(n)=isprime((11*10^n + 19)/3) \\ Charles R Greathouse IV, Mar 16 2016


CROSSREFS

Cf. A056654, A268448, A269303.
Sequence in context: A086771 A156066 A143890 * A272057 A056658 A302164
Adjacent sequences: A270336 A270337 A270338 * A270340 A270341 A270342


KEYWORD

nonn,more


AUTHOR

Robert Price, Mar 15 2016


EXTENSIONS

a(37) from Robert Price, Sep 16 2018


STATUS

approved



