|
%I #8 Jan 17 2019 13:44:08
%S 1,2,12,21,27,30,33,44,46,76,78,83,84,92,582,750,787,3218,3290,5617,
%T 6385,13960,22705,27636,36497,50349,51169,70381,70486,73096
%N Numbers n such that 63*10^n+1 is prime.
%C Numbers such that the digits 63 followed by n-1 occurrences of the digit 0 followed by the digit 1 is prime (see Example section).
%C a(31) > 10^5.
%H Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/primedifficulty.txt">Search for 630w1.</a>
%e 2 is in this sequence because 63*10^2+1 = 6301 is prime.
%e Initial terms and primes associated:
%e a(1) = 1, 631;
%e a(2) = 2, 6301;
%e a(3) = 12, 63000000000001;
%e a(4) = 21, 63000000000000000000001;
%e a(5) = 27, 63000000000000000000000000001, etc.
%t Select[Range[0, 100000], PrimeQ[63*10^#+1] &]
%o (PARI) is(n)=ispseudoprime(63*10^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.
%K nonn,more
%O 1,2
%A _Robert Price_, Apr 05 2016
|
