OFFSET
1,1
COMMENTS
a(6)=73768891456260 might be called a(6.5), since 64*a(6)+1 is prime. But 64*a(6)-1 is 167*1021*44533*621769, alas.
EXAMPLE
a(3) = 211050 because 1*a(3)-1, 1*a(3)+1, 2*a(3)-1, 2*a(3)+1, 4*a(3)-1 and 4*a(3)+1 are all prime.
CROSSREFS
KEYWORD
nonn
AUTHOR
Don Reble, Apr 09 2002
STATUS
approved