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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A272272 Numbers n such that 4^n-3^(n+1) is prime. 0
4, 8, 24, 36, 48, 246, 608, 734, 774, 824, 9348, 1244, 3230, 4656, 5448, 6360, 7598, 15390, 48158, 86754 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(21) > 10^5.

LINKS

Table of n, a(n) for n=1..20.

EXAMPLE

8 is a member since 4^8 - 3^9 = 65536-19683 = 45853 which is a prime number.

MATHEMATICA

Select[Range[4, 100000], PrimeQ[4^# - 3^(# + 1)] &]

PROG

(PARI) lista(nn) = for(n=1, nn, if(ispseudoprime(4^n-3^(n+1)), print1(n, ", "))); \\ Altug Alkan, Apr 24 2016

CROSSREFS

Cf. A093713, A082103, A093717, A093793, A096185, A093794, A093795, A096186, A271883.

Sequence in context: A212019 A075708 A066617 * A024589 A062015 A006640

Adjacent sequences:  A272269 A272270 A272271 * A272273 A272274 A272275

KEYWORD

nonn,more

AUTHOR

Robert Price, Apr 24 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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 16 12:34 EDT 2019. Contains 327098 sequences. (Running on oeis4.)