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 A060778 #19 Dec 11 2024 23:41:24 %S A060778 1,2,1,1,2,2,2,1,1,2,2,2,2,4,1,1,2,2,2,2,4,2,2,1,1,4,2,2,2,2,2,2,4,4, %T A060778 1,1,2,4,4,2,2,2,2,6,2,2,2,1,3,2,2,2,2,4,4,4,4,2,2,2,2,2,1,1,4,2,2,2, %U A060778 4,2,2,2,2,2,6,2,4,2,2,5,1,2,2,4,4,4,4,2,2,4,2,2,4,4,4,2,2,6,3,1,2,2,2,8,4 %N A060778 a(n) = gcd(tau(n+1), tau(n)), where tau = A000005. %H A060778 Harry J. Smith, <a href="/A060778/b060778.txt">Table of n, a(n) for n=1..1000</a> %F A060778 a(n) = gcd(A000005(n+1), A000005(n)). %t A060778 GCD@@@Partition[DivisorSigma[0,Range[110]],2,1] (* _Harvey P. Dale_, May 27 2014 *) %o A060778 (PARI) a(n) = gcd(numdiv(n), numdiv(n+1)); \\ _Michel Marcus_, Jan 12 2018 %o A060778 (Python) %o A060778 from math import gcd %o A060778 from sympy import divisor_count %o A060778 def A060778(n): return gcd(divisor_count(n+1),divisor_count(n)) # _Chai Wah Wu_, Aug 12 2023 %Y A060778 Cf. A000005, A057921, A058074. %K A060778 nonn %O A060778 1,2 %A A060778 _Labos Elemer_, Apr 26 2001