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%I #13 Aug 28 2023 08:20:53
%S 0,0,0,2,0,3,5,0,3,5,8,5,8,12,0,9,8,15,8,10,15,13,15,19,15,12,15,26,0,
%T 19,23,29,17,25,29,17,21,29,30,29,36,29,25,19,35,23,29,43,47,0,44,40,
%U 50,44,40,50,46,47,50,25,42,27,38,27,38,27,42,27,67,50
%N a(n) is the greatest k < n such that A109812(k) AND A109812(n) = A109812(k) or 0 if no such k exists (where AND denotes the bitwise AND operator).
%H Rémy Sigrist, <a href="/A352846/b352846.txt">Table of n, a(n) for n = 1..10000</a>
%H Rémy Sigrist, <a href="/A352846/a352846.png">Scatterplot of the first 500000 terms</a>
%H Rémy Sigrist, <a href="/A352846/a352846.txt">C++ program</a>
%F a(n) = 0 iff A109812(n) is a power of 2.
%e For k = 9:
%e - A109812(9) = 6,
%e - also:
%e k A109812(k) A109812(7) AND A109812(k)
%e - ---------- -------------------------
%e 8 16 0
%e 7 10 2
%e 6 5 4
%e 5 8 0
%e 4 3 2
%e 3 4 4 <- A109812(3)
%e - so a(9) = 3.
%o (C++) See Links section.
%Y Cf. A109812, A352845.
%K nonn,base
%O 1,4
%A _Rémy Sigrist_, Apr 05 2022
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