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 A296081 #11 Oct 18 2022 09:59:43 %S A296081 0,1,1,2,1,1,1,1,2,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,2,1,3,5,1,1,1,1,1,1, %T A296081 1,2,1,1,1,1,1,1,1,1,1,1,1,3,2,1,1,1,1,7,1,7,1,1,1,1,1,1,1,6,1,1,1,5, %U A296081 1,1,1,1,1,1,1,1,1,1,1,1,4,1,1,1,1,1,1,1,1,1,3,1,1,1,1,1,1,5,5,8,1,1,1,1,1 %N A296081 a(n) = gcd(tau(n)-1, sigma(n)-1), where tau = A000005 and sigma = A000203. %H A296081 Antti Karttunen, <a href="/A296081/b296081.txt">Table of n, a(n) for n = 1..16384</a> %F A296081 a(n) = gcd(A032741(n), A039653(n)). %F A296081 a(n) = gcd(A039653(n), A065608(n)). %t A296081 Array[GCD[DivisorSigma[0,#]-1,DivisorSigma[1,#]-1]&,120] (* _Harvey P. Dale_, Oct 18 2022 *) %o A296081 (Scheme) (define (A296081 n) (gcd (A039653 n) (A032741 n))) %Y A296081 Cf. A032741, A039653, A065608, A284288, A296082, A296083. %Y A296081 Cf. also A009205. %K A296081 nonn %O A296081 1,4 %A A296081 _Antti Karttunen_, Dec 05 2017