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 A336386 #11 May 10 2021 14:25:43 %S A336386 0,0,1,-1,1,1,2,-1,-1,1,2,0,1,2,2,-3,2,-1,2,0,3,2,3,0,-1,1,1,1,2,2,4, %T A336386 -2,3,2,3,-2,1,2,2,0,2,3,2,1,0,3,4,-2,0,-1,3,0,3,1,3,1,3,2,3,1,1,4,1, %U A336386 -5,2,3,2,1,4,3,4,-2,1,1,0,1,4,2,4,-2,-2,2,3,2,3,2,3,1,3,0,3,2,5,4,3,-1,2,0,1,-2,2,3,3,0,4 %N A336386 a(n) = bigomega(sigma(n)) - bigomega(n), where bigomega (A001222) gives the number of prime factors with multiplicity, and sigma (A000203) gives the sum of divisors. %H A336386 Antti Karttunen, <a href="/A336386/b336386.txt">Table of n, a(n) for n = 1..65537</a> %H A336386 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a> %F A336386 a(n) = A058063(n) - A001222(n). %F A336386 Additive with a(p^e) = A001222(A000203(p^e)) - A001222(p^e) = A001222(1 + p + p^2 + ... + p^e) - e. %o A336386 (PARI) A336386(n) = (bigomega(sigma(n)) - bigomega(n)); %Y A336386 Cf. A000203, A001222, A058063. %Y A336386 Cf. A336356, A336359 (positions of negative terms), A336360 (of nonnegative terms). %K A336386 sign %O A336386 1,7 %A A336386 _Antti Karttunen_, Jul 20 2020