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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A129962 Primes of the form 2^n + n. 5
3, 11, 37, 521, 32783, 549755813927, 37778931862957161709643, 2417851639229258349412433, 618970019642690137449562201, 266998379490113760299377713271194014325338065294581596243380200977777465722580068752870260867389 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

It is convenient, although not necessary, to let n be an odd number since n even => 2^n + n is even > 2. Conjecture: There is an infinite number of primes in this sequence. If n is prime we have A057664.

LINKS

Hugo Pfoertner, Table of n, a(n) for n = 1..16

EXAMPLE

for n = 3, 2^3+3=11 prime and the second entry.

MATHEMATICA

Select[Table[2^n+n, {n, 600}], PrimeQ[#]&] (* Vladimir Joseph Stephan Orlovsky, Feb 18 2011*)

PROG

(PARI) f(n) = forstep(x=1, n, 2, y=2^x+x; if(isprime(y), print1(y", ")))

(MAGMA) [a: n in [0..400] | IsPrime(a) where a is 2^n + n]; // Vincenzo Librandi, Jul 25 2019

CROSSREFS

Cf. A052007 (values of n), A057664, A081296.

Sequence in context: A183511 A307800 A265796 * A026361 A006189 A092201

Adjacent sequences:  A129959 A129960 A129961 * A129963 A129964 A129965

KEYWORD

nonn

AUTHOR

Cino Hilliard, Jun 10 2007

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 April 7 13:55 EDT 2020. Contains 333305 sequences. (Running on oeis4.)