%I #12 Nov 27 2017 11:37:58
%S 4,36,252,1197,47880,1388520,23604840,153431460,843873030,2953555605,
%T 17721333630,2091117368340,33457877893440,769531191549120,
%U 28472654087317440,2249339672898077760,2249339672898077760,200191230887928920640,9408987851732659270080,1881797570346531854016
%N Denominators of the partial sums of the reciprocals of the numbers (k + 1)*(5*k + 4) = 2*A005476(k+1), for k >= 0.
%C The corresponding numerators are given in A294831. Details are found there.
%F a(n) = denominator(V(5,4;n)) with V(5,4;n) = Sum_{k=0..n} 1/((k + 1)*(5*k + 4)) = Sum_{k=0..n} 1/(2*A005476(k+1)) = Sum_{k=0..n} (1/(k + 4/5) - 1/(k+1)).
%F For this sum in terms of the digamma function Psi see A294831.
%e For the rationals V(5,4;n) see A294831.
%o (PARI) a(n) = denominator(sum(k=0, n, 1/((k + 1)*(5*k + 4)))); \\ _Michel Marcus_, Nov 19 2017
%Y Cf. 2*A005476, A294831.
%K nonn,frac,easy
%O 0,1
%A _Wolfdieter Lang_, Nov 18 2017