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a(n) is the greatest k such that A331587(n) = k * reverse(k) (where reverse(k) is the binary reversal of k, A030101(k)).
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%I #10 Jan 22 2020 12:57:20

%S 1,3,5,7,9,13,15,17,21,25,29,27,31,33,41,49,45,57,53,51,61,59,63,65,

%T 73,81,97,89,85,105,113,101,93,121,99,109,117,107,115,125,123,119,127,

%U 129,145,161,153,177,169,193,165,185,209,201,225,181,197,217,241

%N a(n) is the greatest k such that A331587(n) = k * reverse(k) (where reverse(k) is the binary reversal of k, A030101(k)).

%H Rémy Sigrist, <a href="/A331589/b331589.txt">Table of n, a(n) for n = 1..8347</a>

%H Rémy Sigrist, <a href="/A331589/a331589.gp.txt">PARI program for A331589</a>

%F a(n) = A030101(A331588(n)).

%F a(n) * A331588(n) = A331587(n).

%o (PARI) See Links section.

%Y Cf. A030101, A331587, A331588.

%K nonn,base

%O 1,2

%A _Rémy Sigrist_, Jan 21 2020