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 A376556 #7 Sep 28 2024 07:37:35
%S A376556 0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,2,4,6,2,2,0,0,1,
%T A376556 2,0,0,0,2,0,0,0,1,0,1,6,8,0,0,0,4,4,6,2,2,0,1,1,1,1,1,1,2,0,0,0,0,0,
%U A376556 0,0,2,0,0,0,1,0,2,4,4,0,0,4,8,2,3,6,8
%N A376556 The number of non-unitary square divisors of binomial(n, floor(n/2)).
%H A376556 Amiram Eldar, <a href="/A376556/b376556.txt">Table of n, a(n) for n = 0..10000</a>
%F A376556 a(n) = A056626(A001405(n)).
%t A376556 f1[p_, e_] := 1 + Floor[e/2]; f2[p_, e_] := 2^(1 - Mod[e, 2]); a[0] = a[1] = 0; a[n_] := Times @@ f1 @@@ (fct = FactorInteger[Binomial[n, Floor[n/2]]]) - Times @@ f2 @@@ fct; Array[a, 60, 0]
%o A376556 (PARI) a(n) = {my(e = factor(binomial(n, n\2))[, 2]); vecprod(apply(x -> x\2 + 1, e)) - vecprod(apply(x -> 1 << (1 - x%2), e));}
%Y A376556 Cf. A001405, A056061, A056626, A376553, A376554, A376555.
%K A376556 nonn
%O A376556 0,27
%A A376556 _Amiram Eldar_, Sep 28 2024