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!)
A152580 a(n) = 7^(2^n) + 2. 1
9, 51, 2403, 5764803, 33232930569603, 1104427674243920646305299203 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

These numbers are divisible by 3. This follows by expanding the binomial (6+1)^(2^n) + 2 to get 6h + 1 + 2 for some h. Therefore 3 divides 7^(2^n) + 2.

LINKS

Table of n, a(n) for n=0..5.

FORMULA

a(n) = A165425(n+3) + 2. - R. J. Mathar, Sep 10 2016

MAPLE

A152580:=n->7^(2^n) + 2: seq(A152580(n), n=0..8); # Wesley Ivan Hurt, Jan 22 2017

PROG

(PARI) g(a, n) = if(a%2, b=2, b=1); for(x=0, n, y=a^(2^x)+b; print1(y", "))

(PARI) a(n) = 7^(2^n) + 2; \\ Michel Marcus, Jan 24 2017

CROSSREFS

Cf. A165425.

Sequence in context: A272393 A231748 A181161 * A197722 A172470 A120665

Adjacent sequences:  A152577 A152578 A152579 * A152581 A152582 A152583

KEYWORD

nonn,easy

AUTHOR

Cino Hilliard, Dec 08 2008

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 9 10:52 EDT 2020. Contains 333348 sequences. (Running on oeis4.)