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 A333245 Primes p such that the order of 2 mod p is less than the square root of p. 2
 31, 127, 257, 683, 1103, 1801, 2089, 2113, 2351, 2731, 3191, 4051, 4513, 5419, 6361, 8191, 9719, 11119, 11447, 13367, 14449, 14951, 20231, 20857, 23279, 23311, 26317, 29191, 30269, 32377, 37171, 38737, 39551, 43441, 43691, 49477, 54001, 55633, 55871, 59393 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 EXAMPLE The order of 2 mod 31 is 5, and sqrt(31) = 5.56776436283..., which is more than 5, so 31 is in the sequence. The order of 2 mod 37 is 36, and sqrt(37) = 6.08276253..., which is significantly less than 36, so 37 is not in the sequence. MAPLE q:= p-> is(numtheory[order](2, p)^2 r && return false         m = k >> v         m == 1 && break     end     return true end print([n for n in 3:2:60000 if isA333245(n)]) # Peter Luschny, Mar 16 2020 CROSSREFS Cf. A014664, A002326. Sequence in context: A078656 A095322 A127578 * A158563 A079141 A049203 Adjacent sequences:  A333242 A333243 A333244 * A333246 A333247 A333248 KEYWORD nonn AUTHOR Charles R Greathouse IV, Mar 12 2020 STATUS approved

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Last modified April 16 18:53 EDT 2021. Contains 343050 sequences. (Running on oeis4.)