OFFSET
1,1
COMMENTS
Corresponding primes of the form (3^k + 5^k)/2^3 are listed in {A121938(n)} = {A079773(a(n))} = {19, 421, 10039, 95383574161, 2384331073699, ...}.
No other terms less than 100000. - Robert Price, Apr 28 2012
MATHEMATICA
Do[f=5^n+3^n; If[PrimeQ[f/2^3], Print[{n, f/2^3}]], {n, 1, 1231}]
PROG
(PARI) select(n->isprime((3^n + 5^n)/8), vector(2000, i, i)) \\ Charles R Greathouse IV, Feb 13 2011
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Alexander Adamchuk, Sep 14 2006
EXTENSIONS
a(11)-a(15) from Robert Price, Apr 28 2012
STATUS
approved