login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A224984 Numbers n such that (14^n + 13^n)/27 is prime. 3
7, 13, 311, 1637, 4363, 10433, 41669, 45631 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms are prime.

a(9) > 10^5.

LINKS

Table of n, a(n) for n=1..8.

MATHEMATICA

Select[ Prime[ Range[1, 100000] ], PrimeQ[ (14^# + 13^#)/27 ]& ]

PROG

(PARI) forprime(p=3, 10^6, if(ispseudoprime((14^p + 13^p)/27), print1(p, ", ") ) ); \\ Joerg Arndt, Jul 29 2013

CROSSREFS

Cf. A057180, A128072, A128343, A181141, A187819, A217095, A185239, A213216.

Sequence in context: A084963 A139188 A064119 * A228030 A082706 A201181

Adjacent sequences:  A224981 A224982 A224983 * A224985 A224986 A224987

KEYWORD

hard,nonn,more

AUTHOR

Robert Price, Apr 22 2013

EXTENSIONS

Removed incorrect first term of "2".

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 6 04:14 EST 2019. Contains 329784 sequences. (Running on oeis4.)