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 A328958 #16 Mar 20 2025 22:35:48
%S A328958 1,1,1,1,1,0,1,1,1,0,1,0,1,0,0,1,1,0,1,0,0,0,1,0,1,0,1,0,1,-1,1,1,0,0,
%T A328958 0,1,1,0,0,0,1,-1,1,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,1,0,-1,1,
%U A328958 0,0,-1,1,2,1,0,0,0,0,-1,1,0,1,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,1,1,-1,1,0,-1
%N A328958 a(n) = d(n) - (omega(n) * bigomega(n)), where d (number of divisors) = A000005, omega = A001221, bigomega = A001222.
%C A328958 a(n) = sigma_0(n) - omega(n) * nu(n), where sigma_0 = A000005, nu = A001221, omega = A001222. - The original name of the sequence.
%H A328958 Antti Karttunen, <a href="/A328958/b328958.txt">Table of n, a(n) for n = 1..20000</a>
%H A328958 <a href="/index/Eu#epf">Index entries for sequences computed from exponents in factorization of n</a>.
%F A328958 a(n) = A000005(n) - A001222(n) * A001221(n) = A000005(n) - A113901(n).
%e A328958 a(144) = sigma_0(144) - omega(144) * nu(144) = 15 - 6 * 2 = 3.
%t A328958 Table[DivisorSigma[0,n]-PrimeOmega[n]*PrimeNu[n],{n,100}]
%o A328958 (PARI) A328958(n) = (numdiv(n)-(omega(n)*bigomega(n))); \\ _Antti Karttunen_, Jan 27 2025
%Y A328958 Positions of first appearances are A328962.
%Y A328958 Zeros are A328956.
%Y A328958 Nonzeros are A328957.
%Y A328958 omega(n) * nu(n) is A113901(n).
%Y A328958 (omega(n) - 1) * nu(n) is A307409(n).
%Y A328958 sigma_0(n) - 2 - (omega(n) - 1) * nu(n) is A328959(n).
%Y A328958 Cf. A000005, A001221, A001222, A112798, A124010, A323023, A328960, A328961, A328963, A328964.
%K A328958 sign,easy
%O A328958 1,72
%A A328958 _Gus Wiseman_, Nov 02 2019
%E A328958 More terms added and the function names in the definition replaced with standard OEIS ones - _Antti Karttunen_, Jan 27 2025