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%I #8 Jun 25 2020 09:25:02
%S 1,2,13,4,6,75,22975,11,15,10,1417,37,17,12,573,19,16,49,28,227,34,18,
%T 26,31,1371,20,41,36,8181,339,38,30,40,207,43,70,1113,91,235,32,63,
%U 203,50,60,103,48,189,42,421,57,74,98,65,259,11997,155,44,54,199,67
%N a(k) is the index of the first occurrence of 2*k-1 in A208884, or 0 if it does not occur.
%C It is conjectured that A208884 contains all the odd numbers. If so, a(n) > 0 for every n.
%H Giovanni Resta, <a href="/A335817/b335817.txt">Table of n, a(n) for n = 1..10000</a>
%e The first terms of A208884 are 1, 3, 3, 7, 3, so a(2*1-1) = 1, a(2*2-1) = 2, and a(2*4-1) = 4.
%t b[1]=1; b[n_] := b[n] = #/2^IntegerExponent[#, 2] &@ (n + b[n-1]); A = Transpose@ {b /@ #, #} &@ Range[25000]; A = DeleteDuplicatesBy[ Sort@ A, First]; Last /@ TakeWhile[ A, A[[ (First[#] + 1)/2, 1]] == First@# &]
%Y Cf. A208884.
%K nonn
%O 1,2
%A _Giovanni Resta_, Jun 25 2020
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