OFFSET
1,1
COMMENTS
2^(2*n+1)+2^(n+1)+1 is a factor of 4^(2*n+1)+1.
LINKS
Daniel Suteu, Table of n, a(n) for n = 1..547
EXAMPLE
For n=10, 2^(2*n+1)+2^(n+1)+1 = 2099201 = 13*113*1429, so a(10)=1429.
MATHEMATICA
Table[FactorInteger[2^(2n+1)+2^(n+1)+1][[-1, 1]], {n, 30}] (* Harvey P. Dale, Nov 03 2017 *)
PROG
(PARI) a(n) = {f=factor(2^(2*n+1)+2^(n+1)+1); f[matsize(f)[1], 1]}
CROSSREFS
KEYWORD
nonn
AUTHOR
Colin Barker, Sep 29 2013
STATUS
approved