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 A354346 #12 May 26 2022 20:43:41
%S A354346 1,-1,4,3,4,6,9,4,17,0,20,14,4,-1,1,-53,24,31,32,10,-24,38,42,-10,47,
%T A354346 -14,29,31,38,-53,56,39,61,10,50,67,72,56,63,-146,72,-136,57,78,84,80,
%U A354346 88,-74,95,85,90,-6,96,-37,81,72,-205,38,116,-25,102,106,121,-413,-189,103,68,86,28,62,108,132,88,142,84
%N A354346 a(n) = 2*n - A064989(sigma(sigma(A003961(n)))), where A003961 shifts the prime factorization one step towards larger primes, and A064989 shifts it back towards smaller primes.
%C A354346 No other zeros <= 2^25 than a(10) and a(105270).
%H A354346 Antti Karttunen, <a href="/A354346/b354346.txt">Table of n, a(n) for n = 1..20000</a>
%H A354346 Antti Karttunen, <a href="/A354346/a354346.txt">Data supplement: n, a(n) computed for n = 1..105270</a>
%H A354346 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%H A354346 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A354346 a(n) = 2*n - A354195(n) = 2*n - A064989(sigma(sigma(A003961(n)))).
%o A354346 (PARI)
%o A354346 A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
%o A354346 A064989(n) = { my(f=factor(n>>valuation(n, 2))); for(i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); factorback(f); };
%o A354346 A354195(n) = A064989(sigma(sigma(A003961(n))));
%o A354346 A354346(n) = (n+n - A354195(n));
%Y A354346 Cf. A000203, A003961, A064989, A354195.
%Y A354346 Cf. also A033879.
%K A354346 sign
%O A354346 1,3
%A A354346 _Antti Karttunen_, May 25 2022