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 A054641 #13 Oct 20 2019 02:00:11 %S A054641 1,6,6,6,6,42,42,210,210,210,210,3990,3990,43890,43890,43890,43890, %T A054641 1360590,23130030,23130030,855811110,855811110,855811110,855811110, %U A054641 855811110,855811110,11125544430,11125544430,11125544430,11125544430 %N A054641 GCD of divisor-sum of primorials and primorials itself: a(n) = gcd(A002110(n), A000203(A002110(n))). %C A054641 Values are repeated for several arguments: observed from 1 to 8 times below n=100. Sites of jump seems not so regular. %C A054641 From a sufficiently high value of n, A002110(n) divides the terms. E.g., from n=27, A002110(8) divides the values of this sequences. %H A054641 <a href="/index/Di#divseq">Index to divisibility sequences</a> %o A054641 (PARI) a(n)=gcd(prod(i=1,n,prime(i)),prod(i=1,n,prime(i)+1)) \\ _Charles R Greathouse IV_, Feb 19 2013 %Y A054641 Cf. A002110, A000203, A028815, A054640, A054642. %K A054641 nonn %O A054641 1,2 %A A054641 _Labos Elemer_, May 15 2000