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 A125549 #9 Sep 08 2022 08:45:28 %S A125549 209,510509,9699689,223092869,6469693229,200560490129,7420738134809, %T A125549 13082761331670029,614889782588491409,32589158477190044729, %U A125549 1922760350154212639069,117288381359406970983269 %N A125549 Composite Kummer numbers: -1 + product of first n consecutive primes (A057588). %H A125549 Amiram Eldar, <a href="/A125549/b125549.txt">Table of n, a(n) for n = 1..338</a> %o A125549 (Magma) [a: n in [2..20]| not IsPrime(a) where a is -1+&*[NthPrime(k):k in [1..n]]]; // _Marius A. Burtea_, Feb 18 2020 %Y A125549 Cf. A057588, A066576 (composite Euclid numbers). %K A125549 nonn %O A125549 1,1 %A A125549 _Artur Jasinski_, Jan 01 2007 %E A125549 Edited by _Klaus Brockhaus_, Jan 11 2007