

A161719


Least number k such that 7^(2^i) + k is prime for i = 0,1,..,n1.


0




OFFSET

1,1


LINKS

Table of n, a(n) for n=1..10.


EXAMPLE

a(5) = 990 because k = 990 is the minimal k such that N = 7^(2^i) + k is prime for i = 0, 1, 2, 3, 4; N = 997, 1039, 3391, 5765791, 33232930570591. But 7^(2^5) + 990 is divisible by 37 and four other primes.


CROSSREFS

Cf. A129613, A225560 A226281, A226707.
Sequence in context: A145598 A320392 A117881 * A161433 A180498 A107856
Adjacent sequences: A161716 A161717 A161718 * A161720 A161721 A161722


KEYWORD

nonn,more


AUTHOR

Robin Garcia, Jun 16 2013


EXTENSIONS

a(10) from Giovanni Resta, Jun 16 2013


STATUS

approved



