OFFSET
1,1
COMMENTS
Primes arising from A040076 (or 0 if no such prime exists).
Or: Starting with x=n+1, the first prime created by iterating the map x-> 2*x-1. - Kevin L. Schwartz and Christian N. K. Anderson, May 13 2013
LINKS
R. J. Mathar, Table of n, a(n) for n = 1..382
MAPLE
A050921 := proc(n)
for m from 0 do
if isprime(n*2^m+1) then
return n*2^m+1 ;
end if;
end do;
end proc; # R. J. Mathar, Jun 01 2013
MATHEMATICA
Do[m = 0; While[ !PrimeQ[n*2^m + 1], m++ ]; Print[n*2^m + 1], {n, 1, 47} ]
CROSSREFS
KEYWORD
nonn,easy,nice
AUTHOR
N. J. A. Sloane, Dec 30 1999
EXTENSIONS
The next term (47*2^583 + 1) is too large to show.
STATUS
approved