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 A331289 #13 Jan 15 2020 18:40:10 %S A331289 1,0,0,0,0,0,0,-2,-1,0,0,1,0,0,4,-2,0,-1,0,1,4,0,0,-1,0,0,-2,1,0,2,0, %T A331289 -4,4,0,6,0,0,0,4,-3,0,-2,0,1,-2,0,0,-4,-1,1,4,1,0,-2,2,4,4,0,0,-1,0, %U A331289 0,0,-4,11,9,0,1,4,2,0,-2,0,0,2,1,0,9,0,-3,-3,0,0,-2,9,0,4,4,0,-2,4,1,4,0,5,-4,0,-1,7,-3,0,9,0,4,1 %N A331289 a(n) = A329348(n) - A001222(n). %H A331289 Antti Karttunen, <a href="/A331289/b331289.txt">Table of n, a(n) for n = 1..12571</a> %H A331289 Antti Karttunen, <a href="/A331289/a331289.txt">Data supplement: n, a(n) computed for n = 1..65537</a> %H A331289 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a> %H A331289 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a> %H A331289 <a href="/index/Pri#primorial_numbers">Index entries for sequences related to primorial numbers</a> %F A331289 a(n) = A329348(n) - A001222(n). %F A331289 a(n) = (A331188(n) mod A117366(n)) - A001222(n). %o A331289 (PARI) %o A331289 A002110(n) = prod(i=1, n, prime(i)); %o A331289 A331289(n) = if(1==n, 1, my(f=factor(n), p=nextprime(1+vecmax(f[, 1]))); (prod(i=1, #f~, A002110(primepi(f[i, 1]))^(f[i, 2]-(#f~==i)))%p)-bigomega(n)); %Y A331289 Cf. A001222, A117366, A329348, A329619, A331188, A331290. %K A331289 sign,look %O A331289 1,8 %A A331289 _Antti Karttunen_, Jan 15 2020