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 A078423 #9 Oct 16 2023 13:42:28
%S A078423 2,60,30240,98017920,857180548224000,109720581991308288000,
%T A078423 70265584374661732509573120000,61765285634580106110458762035200000,
%U A078423 642817384174195049892129048242945261568000000
%N A078423 Group the natural numbers into clumps with increasing prime numbers of elements, then multiply the members of each clump.
%F A078423 a(n) = A007504(n)!/A007504(n-1)!. - _Andrew Howroyd_, Oct 16 2023
%e A078423 Dividing 1,2,3,4,5,6,7,8,9,10,... into clumps of 2,3,5,.. elements: {1,2}, {3,4,5}, {6,7,8,9,10}, ... and then multiply each clumps to get 2,60,30240,...
%Y A078423 Cf. A007504, A034956.
%K A078423 nonn
%O A078423 1,1
%A A078423 _Lior Manor_, Dec 29 2002