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 A305567 #4 Jun 05 2018 22:36:19
%S A305567 1,1,1,1,1,2,1,1,1,1,7,1,1,1,1,1,4,2,1,1,2,1,1,7,1,1,1,1,1,32,7,2,1,1,
%T A305567 1,1,1,7,1,1,1,7,1,1,1,8,4,2,1,1,1,1,32,2,7,1,1,1,1,1,32,7,1,2,1,1,7,
%U A305567 1,1,1,7,1,1,1,1,1,136,32,4,7,2,1,1,1,2
%N A305567 Irregular triangle where T(n,k) is the number of finite sets of positive integers with least common multiple n and greatest common divisor k, where k runs over all divisors of n.
%e A305567 Triangle begins:
%e A305567 1
%e A305567 1 1
%e A305567 1 1
%e A305567 2 1 1
%e A305567 1 1
%e A305567 7 1 1 1
%e A305567 1 1
%e A305567 4 2 1 1
%e A305567 2 1 1
%e A305567 7 1 1 1
%e A305567 1 1
%e A305567 32 7 2 1 1 1
%e A305567 1 1
%e A305567 7 1 1 1
%e A305567 7 1 1 1
%e A305567 8 4 2 1 1
%e A305567 1 1
%e A305567 32 2 7 1 1 1
%e A305567 1 1
%e A305567 32 7 1 2 1 1
%t A305567 Table[Length[Select[Subsets[Divisors[n]],And[GCD@@#==k,LCM@@#==n]&]],{n,30},{k,Divisors[n]}]
%Y A305567 Row lengths are A000005.
%Y A305567 Cf. A076078, A181819, A281116, A285572, A290103, A304818, A305563, A305564, A305565, A305566.
%K A305567 nonn,tabf
%O A305567 1,6
%A A305567 _Gus Wiseman_, Jun 05 2018