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 A373146 #6 May 26 2024 21:41:54 %S A373146 0,0,1,-2,5,-2,29,-9,-2,0,209,-12,2309,22,0,-28,30029,-16,510509,-16, %T A373146 22,198,9699689,-39,2,2296,-21,0,223092869,-22,6469693229,-75,198, %U A373146 30012,24,-54,200560490129,510490,2296,-59,7420738134809,-8,304250263527209,164,-29,9699666,13082761331670029,-106,46,-32,30012,2256 %N A373146 a(n) = A276085(n) - A003415(n), where A003415 is the arithmetic derivative and A276085 is the primorial base log-function. %H A373146 Antti Karttunen, <a href="/A373146/b373146.txt">Table of n, a(n) for n = 1..2048</a> %o A373146 (PARI) %o A373146 A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1])); %o A373146 A002110(n) = prod(i=1,n,prime(i)); %o A373146 A276085(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*A002110(primepi(f[k, 1])-1)); }; %o A373146 A373146(n) = (A276085(n) - A003415(n)); %Y A373146 Cf. A003415, A276085, A369650 (positions of 0's), A373145. %K A373146 sign %O A373146 1,4 %A A373146 _Antti Karttunen_, May 26 2024