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Denominators of the higher order exponential integral constants alpha(2,n).
2

%I #12 May 07 2020 06:15:52

%S 1,1,16,1296,20736,12960000,4320000,10372320000,165957120000,

%T 40327580160000,40327580160000,590436101122560000,590436101122560000,

%U 16863445484161436160000,2409063640594490880000,2409063640594490880000

%N Denominators of the higher order exponential integral constants alpha(2,n).

%C See A163927 for information about the constants alpha(k,n).

%F alpha(k,n) = (1/k)*Sum_{i=0..k-1} Sum_{p=0..n-1} p^(-2*(k-i))*alpha(i, n) with alpha(0,n) = 1. For this sequence, k = 2 and n >= 1.

%e alpha(k=2, n=1) = 0, alpha(k=2, 2) = 1, alpha(k=2, 3) = 21/16, and alpha(k=2, 4) = 1897/1296.

%Y Cf. A163928 (numerators).

%K nonn,frac

%O 1,3

%A _Johannes W. Meijer_ & _Nico Baken_, Aug 13 2009, Aug 17 2009