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%I #27 May 07 2024 06:01:22
%S 1,25,94,209,370,577,830,1129,1474,1865,2302,2785,3314,3889,4510,5177,
%T 5890,6649,7454,8305,9202,10145,11134,12169,13250,14377,15550,16769,
%U 18034,19345,20702,22105,23554,25049,26590,28177,29810,31489,33214,34985,36802,38665
%N a(0) = 1, a(n) = 23*n^2 + 2 for n>0.
%H Bruno Berselli, <a href="/A010013/b010013.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F G.f.: (1+x)*(1+21*x+x^2)/(1-x)^3. - _Bruno Berselli_, Feb 06 2012
%F E.g.f.: (x*(x+1)*23+2)*e^x-1. - _Gopinath A. R._, Feb 14 2012
%F Sum_{n>=0} 1/a(n) = 3/4 + sqrt(46)/92*Pi*coth( Pi*sqrt(46)/23) = 1.0677349581... - _R. J. Mathar_, May 07 2024
%F a(n) = A069174(n)+A069174(n+1). - _R. J. Mathar_, May 07 2024
%t Join[{1}, 23 Range[41]^2 + 2] (* _Bruno Berselli_, Feb 06 2012 *)
%Y Cf. A206399.
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_.