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 A109896 #5 Nov 04 2018 13:13:30 %S A109896 4,5,7,7,7,8,10,13,9,9,13,7,7,11,7,13,13,11,11,15,11,13,15,13,15,16, %T A109896 14,11,11,13,9,17,17,19,15,15,13,17,14,8,15,18,20,15,17,17,17,9,19,11, %U A109896 20,20,13,19,19,15,15,9,14,14,17,16,15,18,13,20,14,14,14,17,15,15,15,21,13 %N A109896 Group the natural numbers so that every 2n-th group product is divisible by the single number in the next group. (1), (2,3,4,5), (6), (7,8,9,10,11), (12), (13,14,15,16,17,18,19),(20), (21,22,23,24,25,26,27),(28),... Sequence contains the number of terms in the 2n-th group. %C A109896 a(n) = A109895(x+1)-A109895(x)-1 - Simon Nickerson (simonn(AT)maths.bham.ac.uk), Jul 15 2005 %Y A109896 Cf. A079759, A109895, A109897. %K A109896 nonn %O A109896 1,1 %A A109896 _Amarnath Murthy_, Jul 13 2005 %E A109896 More terms from Simon Nickerson (simonn(AT)maths.bham.ac.uk), Jul 15 2005