

A125744


Primes p such that (3^p + 3^((p + 1)/2) + 1)/7 is prime.


2



11, 37, 47, 97, 167, 877, 2027, 2293, 3011, 6803, 8423, 50221, 152809, 505823
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OFFSET

1,1


COMMENTS

PrimePi[ a(n) ] = {5, 12, 15, 25, 39, 151, 307, 341, ...}.


LINKS



MATHEMATICA

Do[p=Prime[n]; f=(3^p+3^((p+1)/2)+1)/7; If[PrimeQ[f], Print[{n, p}]], {n, 1, 341}]


CROSSREFS



KEYWORD

hard,more,nonn


AUTHOR



EXTENSIONS

a(9)a(12) from Lelio R Paula (lelio(AT)sknet.com.br), May 09 2008


STATUS

approved



