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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
Sequence in context: A223343 A028466 A157105 * A297994 A237216 A228268
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

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Last modified February 26 11:46 EST 2024. Contains 370352 sequences. (Running on oeis4.)