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 A242959 Numbers n such that 5^A000010(n) == 1 (mod n^2). 11
 2, 20771, 40487, 41542, 80974, 83084, 161948, 643901, 1255097, 1287802, 1391657, 1931703, 2510194, 2575604, 2783314, 3765291, 3863406, 4174971, 5020388, 5151208, 5566628, 7530582, 7726812, 8349942, 10040776, 11133256, 15061164, 15308227, 15453624, 16699884 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Giovanni Resta, Table of n, a(n) for n = 1..479 (terms < 10^15, first 75 terms from Felix Fröhlich) PROG (PARI) for(n=2, 10^9, if(Mod(5, n^2)^(eulerphi(n))==1, print1(n, ", "))) CROSSREFS Cf. A077816, A242958, A242960. If a(n) is prime, then a(n) is in A123692. Sequence in context: A124364 A173156 A214598 * A123692 A290741 A261362 Adjacent sequences:  A242956 A242957 A242958 * A242960 A242961 A242962 KEYWORD nonn AUTHOR Felix Fröhlich, May 27 2014 STATUS approved

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Last modified April 8 05:55 EDT 2020. Contains 333312 sequences. (Running on oeis4.)