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 A294827 #10 Nov 17 2017 04:06:47
%S A294827 2,7,252,2142,58905,1060290,16964640,627691680,627691680,29501508960,
%T A294827 383519616480,7286872713120,225893054106720,15134834625150240,
%U A294827 15134834625150240,15134834625150240,620528219631159840,17995318369303635360,413892322493983613280,8029511056383282097632
%N A294827 Denominators of the partial sums of the reciprocals of twice the heptagonal numbers (k + 1)*(5*k + 2) = A135706(k+1) = 2*A000566(k+1), for k >= 0.
%C A294827 The corresponding numerators are given in A294826. Details are found there.
%F A294827 a(n) = denominator(V(5,2;n)) with V(5,2;n) = Sum_{k=0..n} 1/((k + 1)*(5*k + 2)) = Sum_{k=0..n} 1/A135706(k+1) = (1/3)*Sum_{k=0..n} (1/(k + 2/5) - 1/(k+1)). For this formula in terms of the digamma function see A294826.
%e A294827 See A294826 for the rationals.
%o A294827 (PARI) a(n) = denominator(sum(k=0, n, 1/((k + 1)*(5*k + 2)))); \\ _Michel Marcus_, Nov 17 2017
%Y A294827 Cf. A000566, A135706, A294826.
%K A294827 nonn,frac,easy
%O A294827 0,1
%A A294827 _Wolfdieter Lang_, Nov 16 2017