OFFSET
1,1
COMMENTS
a(14) has 671 digits. a(15) has 2820 digits (not included in b-file).
Alternately, primes of the form Jacobsthal(n) - n, where Jacobsthal(n) is the n-th Jacobsthal number.
LINKS
K. D. Bajpai, Table of n, a(n) for n = 1..14
EXAMPLE
a(2)= 1398079: n=22: ((2^n-(-1)^n)/3-n)= 1398079, which is prime.
a(4)= 393530540239137101071: n=70: ((2^n-(-1)^n)/3-n)= 393530540239137101071, which is prime.
MAPLE
KD := proc() local a; a:= (2^n -(-1)^n)/3-n; if isprime(a)then RETURN (a); fi; end: seq(KD(), n=1..1000);
PROG
(PARI) for(n=8, 500, if(ispseudoprime(t=2^n\/3-n), print1(t", "))) \\ Charles R Greathouse IV, Nov 13 2013
CROSSREFS
KEYWORD
nonn,less
AUTHOR
K. D. Bajpai, Nov 13 2013
EXTENSIONS
Definition corrected by Charles R Greathouse IV, Nov 13 2013
STATUS
approved