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A225126 Central terms of the triangle in A048152.

%I A225126 #18 Jun 20 2017 01:35:18
%S A225126 0,1,4,2,7,3,10,4,13,5,16,6,19,7,22,8,25,9,28,10,31,11,34,12,37,13,40,
%T A225126 14,43,15,46,16,49,17,52,18,55,19,58,20,61,21,64,22,67,23,70,24,73,25,
%U A225126 76,26,79,27,82,28,85,29,88,30,91,31,94,32,97,33,100
%N A225126 Central terms of the triangle in A048152.
%C A225126 a(n) = A123684(n) for n > 1;
%C A225126 a(n) = A048152(2*n-1,n), central terms;
%C A225126 also a(n) = A060036(2*n-1,n-1) for n > 1.
%C A225126 a(n+1)=the remainder when n^2 is divided by 2n+1. - _J. M. Bergot_, Jun 25 2013
%H A225126 Reinhard Zumkeller, <a href="/A225126/b225126.txt">Table of n, a(n) for n = 1..1000</a>
%H A225126 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,2,0,-1).
%F A225126 a(1) = 0, a(2*n) = n and a(2*n+1) = 3*n+1.
%F A225126 a(n) = 2*a(n-2)-a(n-4) for n>5. G.f.: -x^2*(x^3-4*x-1) / ((x-1)^2*(x+1)^2). - _Colin Barker_, May 01 2013
%o A225126 (Haskell)
%o A225126 a225126 n = a048152 (2 * n - 1)  n
%o A225126 (PARI) a(n)=n--^2%(2*n+1) \\ _Charles R Greathouse IV_, Jun 25 2013
%K A225126 nonn,easy
%O A225126 1,3
%A A225126 _Reinhard Zumkeller_, Apr 29 2013