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A070193 Numbers n such that gcd(3n,8^n+1) = 3 but n does not divide the numerator of B(2n) (the Bernoulli numbers). 4

%I #10 Jun 24 2014 01:08:24

%S 253,1081,1771,2485,2783,3289,4301,4807,5405,5819,7337,7567,7843,9361,

%T 10373,10879,11891,12397,12425,13409,13861,14053,14927,15433,17395,

%U 17963,18145,18377,18469,19481,19987,20539,20999,22517,23023,24541

%N Numbers n such that gcd(3n,8^n+1) = 3 but n does not divide the numerator of B(2n) (the Bernoulli numbers).

%C Equivalently, n is in A070191 but not in A069040.

%t testb[n_] := Select[First/@FactorInteger[n], Mod[2n, #-1]==0&]=={}; test8[n_] := GCD[3n, PowerMod[8, n, 3n]+1]==3; Select[Range[25000], test8[ # ]&&!testb[ # ]&]

%Y Cf. A069040, A070191, A070192.

%K nonn

%O 1,1

%A _Benoit Cloitre_ and _Dean Hickerson_, Apr 26 2002

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Last modified February 29 13:45 EST 2024. Contains 370425 sequences. (Running on oeis4.)