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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A061421 Primes of the form 2^n+n+1. 8
2, 7, 71, 110427941548649020598956093796432407239217743554726184882600387580788973 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Next term is 2^1884+1884+1, with 568 digits and is too large to include. - Emeric Deutsch, May 13 2006

The Wikipedia article "Zeisel number" gives a historical connection to A051015. - Jonathan Sondow, Oct 17 2017

LINKS

Table of n, a(n) for n=1..4.

K. S. Brown, The Sum of the Prime Factors of N (Part 2: Primes of the Form 2k-1 + k), Math Pages

Wikipedia, Zeisel number

MAPLE

a:=proc(n) if isprime(2^n+n+1)=true then 2^n+n+1 else fi end: seq(a(n), n=0..1000); # Emeric Deutsch, May 13 2006

MATHEMATICA

{ta={{0}}, tb={{0}}}; Do[g=n; s=2^n+n+1; If[PrimeQ[s], Print[n]; ta=Append[ta, n]; tb=Append[tb, s]], {n, 1, 10000}]; {ta, tb, g} (* Labos Elemer, Nov 19 2004 *)

CROSSREFS

Cf. A001580, A069539, A052007, A048744, A100357, A100358, A100359.

Cf. A061422.

Sequence in context: A230459 A267406 A100360 * A304192 A141315 A215637

Adjacent sequences:  A061418 A061419 A061420 * A061422 A061423 A061424

KEYWORD

nonn

AUTHOR

Jason Earls, May 02 2001

EXTENSIONS

Edited by N. J. A. Sloane, May 04 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 August 23 11:24 EDT 2019. Contains 326222 sequences. (Running on oeis4.)