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 A211522 #17 Mar 12 2025 08:20:22
%S A211522 0,0,0,1,2,3,4,6,8,11,13,16,19,23,27,31,35,40,45,51,56,62,68,75,82,89,
%T A211522 96,104,112,121,129,138,147,157,167,177,187,198,209,221,232,244,256,
%U A211522 269,282,295,308,322,336,351,365,380,395,411,427,443,459,476
%N A211522 Number of ordered triples (w,x,y) with all terms in {1,...,n} and w + 5y = 2x.
%C A211522 For a guide to related sequences, see A211422.
%H A211522 Colin Barker, <a href="/A211522/b211522.txt">Table of n, a(n) for n = 0..1000</a>
%H A211522 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1,0,1,-1,-1,1).
%F A211522 a(n) = a(n-1) + a(n-2) - a(n-3) + a(n-5) - a(n-6) - a(n-7) + a(n-8).
%F A211522 G.f.: x^3*(1 + x + x^4) / ((1 - x)^3*(1 + x)*(1 + x + x^2 + x^3 + x^4)). - _Colin Barker_, Dec 02 2017
%F A211522 a(n) ~ 3*n^2/20. - _Stefano Spezia_, Mar 11 2025
%t A211522 t[n_] := t[n] = Flatten[Table[w - 2 x + 5 y, {w, 1, n}, {x, 1, n}, {y, 1, n}]]
%t A211522 c[n_] := Count[t[n], 0]
%t A211522 t = Table[c[n], {n, 0, 70}] (* A211522 *)
%t A211522 FindLinearRecurrence[t]
%t A211522 LinearRecurrence[{1,1,-1,0,1,-1,-1,1},{0,0,0,1,2,3,4,6},58] (* _Ray Chandler_, Aug 02 2015 *)
%o A211522 (PARI) concat(vector(3), Vec(x^3*(1 + x + x^4) / ((1 - x)^3*(1 + x)*(1 + x + x^2 + x^3 + x^4)) + O(x^40))) \\ _Colin Barker_, Dec 02 2017
%Y A211522 Cf. A211422.
%K A211522 nonn,easy
%O A211522 0,5
%A A211522 _Clark Kimberling_, Apr 14 2012