OFFSET
1,2
COMMENTS
EXAMPLE
a(1)=1 because 2*1^2-1=1 is nonprime and 2*1^2+1=3 is prime.
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Mar 01 2010
EXTENSIONS
37 removed by R. J. Mathar, Mar 09 2010
STATUS
approved