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 A063974 #15 Dec 24 2024 07:31:20
%S A063974 1,0,1,1,1,1,0,1,1,1,0,2,0,1,0,0,1,2,0,2,0,0,0,3,0,1,0,1,0,3,0,2,1,0,
%T A063974 0,2,0,1,0,1,0,2,0,1,0,0,0,3,0,2,0,0,0,3,0,1,0,0,0,4,0,1,0,0,1,0,0,2,
%U A063974 0,1,0,6,0,1,0,0,0,1,0,3,0,1,0,3,0,0,0,0,0,4,0,0,0,0,0,4,0,1,0,1,0,2,0,2,0
%N A063974 Number of terms in inverse set of usigma = sum of unitary divisors = A034448.
%H A063974 Amiram Eldar, <a href="/A063974/b063974.txt">Table of n, a(n) for n = 1..10000</a>
%F A063974 Size of set {x; usigma(x) = n}.
%F A063974 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = A308041. - _Amiram Eldar_, Dec 23 2024
%e A063974 usigma(x) = 288, invusigma(288) = {138,154,165,168,213,235,248,253}, so a(288) = 8, the number of all terms in the inverse set.
%Y A063974 Cf. A034444, A034448, A051444, A054973, A057637, A308041.
%K A063974 nonn
%O A063974 1,12
%A A063974 _Labos Elemer_, Sep 05 2001