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 A130421 Numbers k such that 4^k == 2 (mod k). 11
 1, 2, 14, 1022, 20066, 80519, 107663, 485918, 1284113, 1510313, 2531678, 3677198, 3933023, 4557713, 8277458, 8893262, 21122318, 24849833, 26358638, 39852014, 42448478, 71871113, 76712318, 80646143, 98058097, 104832833, 106694033, 131492498, 144322478, 146987033, 164360606, 168204191, 175126478, 176647378, 188997463, 196705598 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Some terms above 10^15: 26435035805519327, 158975398896178078, 64044049390757098943, 1063423126446412987081943, 1091220919655042176978844783, 81074850280355100090334498663, 6317483763950169936179578094903, 5672799393875320397186007124651847, 170923900137537174138295268515194974, 195746953975871672436191077726091399305155458, 325665752547333314939363628501536024940097079718953, 953533053776414279913696071891872697927468471633033, 85791212788381063775490416118630897060666265030605503, 334519297382630382793758729321508383611586565722054114034741260213364710519401967713. - Max Alekseyev, Jun 18 2014 LINKS Max Alekseyev, Table of n, a(n) for n = 1..2617 (all terms below 10^15) MATHEMATICA Join[{1, 2}, Select[Range[107000000], PowerMod[4, #, #]==2&]] (* Harvey P. Dale, Jun 13 2013 *) CROSSREFS Cf. A006935 (odd terms times 2), A130422, A347906 (odd terms), A347908 (even terms). Sequence in context: A225163 A319540 A190634 * A347908 A227403 A156736 Adjacent sequences: A130418 A130419 A130420 * A130422 A130423 A130424 KEYWORD nonn AUTHOR Jon E. Schoenfield, May 26 2007 EXTENSIONS Terms a(28) onward from Max Alekseyev, Jun 18 2014 b-file corrected by Max Alekseyev, Oct 09 2016 STATUS approved

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Last modified March 28 03:48 EDT 2023. Contains 361577 sequences. (Running on oeis4.)