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%I #3 Nov 11 2010 07:34:06
%S 0,4,28,124,601,8188,131068,524284,5758678,269332797,2147483644,
%T 60499757946,322343434415,5567835897839,16557488261208,
%U 7853427629182494,426047939903614778,2305843009213693948,141920345591572240917
%N Residues of 3^(2^(p(n)-1)) for Mersenne numbers with prime indices.
%C Mp is prime iff 3^(2^(p(n)-1)) is congruent to (-3) Mod Mp. Thus M7 = 127 is prime because 3^64 Mod 127 = 124 (=127-3) while M11 = 2047 is composite because 3^1024 Mod 2047 <> 2044.
%H Dennis Martin, <a href="/A131459/b131459.txt">Table of n, a(n) for n = 1..100</a>
%F a(n) = 3^(2^(p(n)-1)) Mod 2^p(n)-1
%e a(5) = 3^(2^(11-1)) Mod 2^11-1 = 3^1024 Mod 2047 = 601
%Y Cf. A095847, A001348, A131458, A131460, A131461, A131462, A131463.
%K nonn
%O 1,2
%A Dennis Martin (dennis.martin(AT)dptechnology.com), Jul 13 2007, Jul 20 2007
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