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 A076638 #38 Feb 16 2025 08:32:47
%S A076638 12,20,2520,27720,720720,4084080,5173168,80313433200,2329089562800,
%T A076638 13127595717600,485721041551200,2844937529085600,1345655451257488800,
%U A076638 3099044504245996706400,54749786241679275146400,3230237388259077233637600
%N A076638 Denominators of harmonic numbers when the numerators are divisible by squares of primes >= 5 in the case of Wolstenholme's Theorem.
%C A076638 From _Bernard Schott_, Dec 28 2018: (Start)
%C A076638 By Wolstenholme's Theorem, if p prime >= 5, the numerator of the harmonic number H_{p-1} is always divisible by p^2. The obtained quotients are in A061002.
%C A076638 The numerators of H_7 and H_{29} are also divisible by prime squares, respectively by 11^2 and 43^2, but not in the case of Wolstenholme's theorem, so the denominators of H_7 and H_{29} are not in this sequence here. (End)
%H A076638 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/WolstenholmesTheorem.html">Wolstenholme's Theorem</a>
%e A076638 a(1)=12 because the numerator of H_4 = 25/12 is divisible by the square of 5;
%e A076638 a(2)=20 because the numerator of H_6 = 49/20 is divisible by the square of 7.
%t A076638 a[p_] := Denominator[HarmonicNumber[p - 1]]; a /@ Prime@Range[3, 20] (* _Amiram Eldar_, Dec 28 2018 *)
%Y A076638 Cf. A076637, A185399.
%K A076638 nonn,frac
%O A076638 1,1
%A A076638 Michael Gilleland (megilleland(AT)yahoo.com), Oct 23 2002
%E A076638 More terms added by _Amiram Eldar_, Dec 04 2018