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%I #11 Apr 25 2021 15:12:17
%S 1,2,3,6,5,10,7,14,16,18,11,22,13,26,21,30,17,34,19,38,25,42,23,46,48,
%T 50,39,54,29,58,31,62,64,66,51,70,37,74,57,78,41,82,43,86,55,90,47,94,
%U 96,98,75,102,53,106,81,110,112,114,59,118,61,122,93,126
%N a(n) is the least k such that A060681(k) = n.
%H Rémy Sigrist, <a href="/A338702/b338702.txt">Table of n, a(n) for n = 0..10000</a>
%F a(n) <= 2*n for any n > 0.
%e The first terms of A060681 are: 0, 1, 2, 2, 4, 3, 6, 4, 6, 5, 10.
%e So: a(0) = 1, a(1) = 2, a(2) = 3, a(4) = 5, a(3) = 6, a(6) = 7, a(10) = 11.
%o (PARI) A060681(n) = if (n==1, 0, my (d=divisors(n)); d[#d]-d[#d-1])
%o { u=0; a=vector(64, n, -1); for (k=1, oo, v=A060681(k); if (v<#a && a[1+v]<0, a[1+v]=k; while (a[1+u]>=0, print1 (a[u++]", "); if (u==#a, break (2))))) }
%Y Cf. A060681.
%K nonn
%O 0,2
%A _Rémy Sigrist_, Apr 24 2021
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