%I #14 Jul 25 2015 09:42:50
%S 1,0,1,4,9,16,25,36,49,64,81,100,121,144,169,196,225,256,289,324,361,
%T 400,441,484,529,576,625,676,729,784,841,900,961,1024,1089,1156,1225,
%U 1296,1369,1444,1521,1600,1681,1764,1849,1936,2025
%N Denominator of 1 - 1/n^2, using 0 at the pole where n=0.
%C From Lyman antispectrum of hydrogen.
%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F a(n) = A000290(n), n>=0.
%o (PARI) a(n)=n^2 \\ _Charles R Greathouse IV_, Nov 26 2012
%Y Main sequence is A000290.
%K nonn,easy,less
%O -1,4
%A _Paul Curtz_, Dec 02 2010