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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A181628 Numbers n such that (2^n + 3^n)/13 is prime. 2
6, 10, 14, 22, 34, 38, 82, 106, 218, 334, 4414, 7246 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms are of the form 2p, p prime.

The prime (2^4414 + 3^4414)/13 = 79300327387 ...611266 985181 has 2105 decimal digits.

LINKS

Table of n, a(n) for n=1..12.

EXAMPLE

10 is in the sequence because (2^10+ 3^10)/13 = 60073/13 = 4621 is prime.

MAPLE

with(numtheory):for n from 1 to 4500 do: x:= (2^n + 3^n)/13:if floor(x)=x and

  type(x, prime)=true then printf(`%d, `, n):else fi:od:

CROSSREFS

Cf. A057469

Sequence in context: A207574 A278972 A241817 * A023387 A119623 A129119

Adjacent sequences:  A181625 A181626 A181627 * A181629 A181630 A181631

KEYWORD

nonn

AUTHOR

Michel Lagneau, Nov 18 2010

EXTENSIONS

a(12) from D. S. McNeil, Nov 18 2010

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified March 27 02:08 EDT 2017. Contains 284143 sequences.