OFFSET
1,1
EXAMPLE
a(1)=2 because k(2)=1 (2*1*2+1=5 is prime);
a(2)=7 because k(7)=2 (2*1*7+1=15 is not prime, 2*2*7+1=29 is prime).
CROSSREFS
KEYWORD
nonn
AUTHOR
Mike Oakes, Oct 01 2002
EXTENSIONS
a(30)-a(38) from Don Reble, Jan 07 2013
a(39)-a(44) from Marco Frigerio, Mar 25 2019
STATUS
approved