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!)
A122711 Even numbers n such that n+2 divides n+2^n. 2
106976, 1642796, 21879936, 96593696, 6926872352, 21235295216, 24936246176, 25867010016, 80832867116, 82230049056, 208329074876, 360598467776, 533800559216, 587627376176, 661575990912, 662312961696, 664490433776, 737374205276, 831623487276, 1052816473676, 1137732817376, 1213045642656, 1270015920636 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Same as even numbers n such that 2^n == 2 (mod n+2). - Robert G. Wilson v, Sep 27 2006

n must be a multiple of 4. A002326(n/4) must not be divisible by 2 or 3. If p is an odd prime factor of n+2, (n+2)/p mod A002326((p-1)/2)=3. - Martin Fuller, Oct 09 2006

Also, the positive numbers A015922(k)-2 that are multiples of 4. E.g., a(1) = 106976 = A015922(3926)-2. Hence, a(n)+2 forms a subsequence of A015922 (and of A130134) consisting of the terms congruent to 2 modulo 4. - Max Alekseyev, Apr 03 2014

LINKS

Max Alekseyev, Table of n, a(n) for n = 1..110 (all terms below 10^15)

MATHEMATICA

Do[ If[ PowerMod[2, 2n, 2n + 2] == 2, Print@2n], {n, 10^9}] (* Robert G. Wilson v, Sep 27 2006 *)

CROSSREFS

Cf. A081765, A015922, A122042.

Sequence in context: A223343 A028466 A157105 * A297994 A237216 A228268

Adjacent sequences:  A122708 A122709 A122710 * A122712 A122713 A122714

KEYWORD

nonn

AUTHOR

Zak Seidov, Sep 23 2006

EXTENSIONS

More terms from Max Alekseyev, Sep 23 2006, Oct 01 2006

More terms from Martin Fuller, Oct 09 2006

Terms a(18) onward from Max Alekseyev, Apr 09 2014

b-file corrected by Max Alekseyev, Oct 11 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 June 12 18:38 EDT 2021. Contains 344959 sequences. (Running on oeis4.)