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a(n) = 5^n mod 163.
2

%I #11 Sep 08 2022 08:46:16

%S 1,5,25,125,136,28,140,48,77,59,132,8,40,37,22,110,61,142,58,127,146,

%T 78,64,157,133,13,65,162,158,138,38,27,135,23,115,86,104,31,155,123,

%U 126,141,53,102,21,105,36,17,85,99,6,30,150,98,1,5,25,125,136,28

%N a(n) = 5^n mod 163.

%C Period 54: repeat [1, 5, 25, 125, 136, 28, 140, 48, 77, 59, 132, 8, 40, 37, 22, 110, 61, 142, 58, 127, 146, 78, 64, 157, 133, 13, 65, 162, 158, 138, 38, 27, 135, 23, 115, 86, 104, 31, 155, 123, 126, 141, 53, 102, 21, 105, 36, 17, 85, 99, 6, 30, 150, 98].

%H Felix Fröhlich, <a href="/A271380/b271380.txt">Table of n, a(n) for n = 0..10000</a>

%F a(n) = a(n-54).

%t PowerMod[5, Range[0, 100], 163]

%o (Magma) [Modexp(5, n, 163): n in [0..100]];

%o (Sage) [power_mod(5, n, 163) for n in (0..60)] # _Bruno Berselli_, Apr 07 2016

%o (PARI) a(n) = lift(Mod(5, 163)^n) \\ _Felix Fröhlich_, Apr 07 2016

%Y Cf. similar sequences listed in A271378.

%K nonn,easy

%O 0,2

%A _Vincenzo Librandi_, Apr 07 2016