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%I #10 Sep 17 2018 20:28:36
%S 1,8,10,17,19,26,27,28,35,37,44,46,53,55,62,64,71,73,80,82,89,91,98,
%T 100,107,109,116,118,125,127,134,136,143,145,152,154,161,163,170,172,
%U 179,181,188,190,197,199,206,208,215,216,217,224,226,233,235,242,244
%N Numbers of the form 27^i*(9*j +- 1).
%C {+-a(n)} gives all nonzero cubes modulo all powers of 3, that is, cubes over 3-adic integers. So this sequence is closed under multiplication.
%H Jianing Song, <a href="/A319293/b319293.txt">Table of n, a(n) for n = 1..9231</a> (all terms <= 40000)
%F a(n) = 13*n/3 + O(log(n)).
%o (PARI) isA319293(n)= n\27^valuation(n, 27)%9==1||n\27^valuation(n, 27)%9==8
%Y A056020 is a proper subsequence.
%Y Perfect powers over 3-adic integers:
%Y Squares: positive: A055047; negative: A055048 (negated);
%Y Cubes: this sequence.
%K nonn
%O 1,2
%A _Jianing Song_, Sep 16 2018
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