This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A156126 #14 Sep 08 2022 08:45:41
%S A156126 1,35,84,165,286,455,680,969,1330,1771,2300,2925,3654,4495,5456,6545,
%T A156126 7770,9139,10660,12341,14190,16215,18424,20825,23426,26235,29260,
%U A156126 32509,35990,39711,43680
%N A156126 Sequence related to Hankel transform of super-ballot numbers.
%C A156126 Hankel transform of A007272 is 10,35,84,... with g.f. (10-5x+4x^2-x^3)/(1-x)^4.
%C A156126 Hankel transform of A156125 is 10^(n^2-1+0^n)*A156126(n).
%H A156126 Vincenzo Librandi, <a href="/A156126/b156126.txt">Table of n, a(n) for n = 0..1000</a>
%H A156126 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F A156126 G.f.: (1+31x-50x^2+35x^3-9x^4)/(1-x)^4.
%F A156126 a(n) = (2*n+5)*(2*n+3)*(n+2)/3, n>0. - R. J. Mathar, Oct 13 2011
%t A156126 CoefficientList[Series[(1+31x-50x^2+35x^3-9x^4)/(1-x)^4,{x,0,40}],x] (* _Vincenzo Librandi_, Jun 30 2012 *)
%t A156126 LinearRecurrence[{4,-6,4,-1},{1,35,84,165,286},40] (* _Harvey P. Dale_, Mar 25 2022 *)
%o A156126 (Magma) I:=[1, 35, 84, 165, 286]; [n le 5 select I[n] else 4*Self(n-1)-6*Self(n-2)+4*Self(n-3)-Self(n-4): n in [1..50]]; // _Vincenzo Librandi_, Jun 30 2012
%K A156126 easy,nonn
%O A156126 0,2
%A A156126 _Paul Barry_, Feb 04 2009