The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A274711 Numbers n such that 5^n + 4^(n+1) is prime. 0
 0, 2, 6, 34, 282, 3662, 87206 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(8) > 10^5. LINKS EXAMPLE 6 is a member since 5^6 + 4^7 = 15625 + 16384 = 32009 which is a prime number. MATHEMATICA Select[Range[0, 100000], PrimeQ[5^# + 4^(# + 1)] &] PROG (PARI) lista(nn) = for(n=0, nn, if(ispseudoprime(5^n + 4^(n+1)), print1(n, ", "))); \\ Altug Alkan, Jul 03 2016 CROSSREFS Cf. A093713, A082103, A093717, A093793, A096185, A093794, A093795, A096186, A271883, A271884. Sequence in context: A325296 A052878 A168362 * A076863 A191742 A181082 Adjacent sequences:  A274708 A274709 A274710 * A274712 A274713 A274714 KEYWORD nonn,more AUTHOR Robert Price, Jul 03 2016 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.

Last modified January 25 03:49 EST 2020. Contains 331241 sequences. (Running on oeis4.)