OFFSET
1,1
COMMENTS
(p - 1) / 2 is often prime.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MAPLE
A158035 := proc(n) local i, am, p, tren;
am := [ ]:
for i from 2 to n do
p := ithprime(i):
tren := (2^(p) - 2^((p - 1) / 2 + 1) + 4*p^(2) - 8*p) / (2*p^(2) - 2*p):
if (type( tren, 'integer') = 'true') then
am := [op(am), p]:
fi
od; RETURN(am) end:
A158035(740); # Jani Melik, May 06 2013
MATHEMATICA
Select[Prime[Range[800]], IntegerQ[(2^#-2^((#-1)/2+1)+4#^2-8#)/(2#^2-2#)]&] (* Harvey P. Dale, Nov 08 2017 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Reikku Kulon, Mar 11 2009
STATUS
approved