This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A343926 #23 Nov 04 2023 12:47:02 %S A343926 1,0,2,4,8,16,32,64,6,256,512,12,2048,4096,24,36,32768,48,131072,72, %T A343926 96,1048576,2097152,144,216,16777216,30,288,134217728,432,536870912, %U A343926 576,1536,4294967296,864,60,34359738368,68719476736,6144,1728,549755813888,2592,2199023255552 %N A343926 a(n) is the least k such that A343443(k) = n or 0 if there is no such k. %C A343926 The indices for which a(n) = 2^(n-2) appear to be A232803. - _Michel Marcus_, May 05 2021 %C A343926 This is true. We can check it for n <= 10. For n > 10 there are only primes and twice primes in A232803. Any number k > 10 not in A232803 can be factored as k = m*p where m, p > 2 and m >= p. We then have A343443(2^(m-2)*3^(p-2)) = m*p = k. But 2^(k-2) = 2^(m*p-2) > 2^(m-2)*3^(p-2). As m, p > 2 we have 2^(m-2)*3^(p-2) not in A232803. - _David A. Corneth_, May 05 2021 %H A343926 David A. Corneth, <a href="/A343926/b343926.txt">Table of n, a(n) for n = 1..3325</a> (first 52 terms from Michel Marcus) %F A343926 a(n) <= 2^(n-2) for n >= 3. %Y A343926 Cf. A025487, A232803, A343443. %K A343926 nonn %O A343926 1,3 %A A343926 _Michel Marcus_, May 04 2021