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 A306013 #4 Jun 26 2018 06:57:30
%S A306013 1,2,3,4,5,7,8,9,11,13,16,17,19,23,25,27,29,31,32,36,37,41,43,47,49,
%T A306013 53,59,61,64,67,71,73,79,81,83,89,97,100,144,196,225,324,400,441,484,
%U A306013 576,676,784,1089,1156,1225,1296,1444,1521,1600,1936,2025,2116
%N A306013 Let P(m) be the product of unitary divisors of m; then a(n) is the position of P(n) when all the numbers P(m) are arranged in increasing order.
%C A306013 P(m) = A061537(m).
%t A306013 z = 100; r[n_] := Select[Divisors[n], GCD[#, n/#] == 1 &];
%t A306013 k[n_] := Length[r[n]];
%t A306013 Table[r[n], {n, 1, z}]
%t A306013 a[n_] := Apply[Times, r[n]]
%t A306013 u = Table[a[n], {n, 1, z}]
%t A306013 Sort[u]
%Y A306013 Cf. A077610, A229994, A229996, A305995, A306010, A306011, A306012.
%K A306013 nonn
%O A306013 1,2
%A A306013 _Clark Kimberling_, Jun 24 2018