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 A137359 #13 Mar 17 2024 15:22:32
%S A137359 0,0,0,0,0,1,4,10,20,35,58,98,176,333,640,1213,2242,4052,7226,12835,
%T A137359 22842,40788,72952,130344,232200,412190,729466,1288216,2272012,
%U A137359 4003795,7050358,12404345,21801674,38275760,67125420,117604174,205865368,360090917,629414866
%N A137359 a(n) = Sum_{k <= n/2 } k*binomial(n-2k, 3k).
%D A137359 D. E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.1.4.
%H A137359 Alois P. Heinz, <a href="/A137359/b137359.txt">Table of n, a(n) for n = 0..1000</a>
%H A137359 <a href="/index/Rec#order_10">Index entries for linear recurrences with constant coefficients</a>, signature (6,-15,20,-15,8,-7,6,-2,0,-1).
%F A137359 G.f.: x^5*(1-x)^2/(x^5+x^3-3*x^2+3*x-1)^2. - _Alois P. Heinz_, Oct 23 2008
%p A137359 a:= n-> (Matrix([[10, 4, 1, 0$7]]). Matrix (10, (i,j)-> if i=j-1 then 1 elif j=1 then [6, -15, 20, -15, 8, -7, 6, -2, 0, -1][i] else 0 fi)^n)[1,8]: seq (a(n), n=0..50); # _Alois P. Heinz_, Oct 23 2008
%t A137359 LinearRecurrence[{6, -15, 20, -15, 8, -7, 6, -2, 0, -1}, {0, 0, 0, 0, 0, 1, 4, 10, 20, 35}, 50] (* _Paolo Xausa_, Mar 17 2024 *)
%Y A137359 Cf. A137356-A137361, A136444.
%K A137359 nonn,base
%O A137359 0,7
%A A137359 _Don Knuth_, Apr 11 2008