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 A014769 #24 Apr 07 2025 17:13:31
%S A014769 1,25,1225,2601,13689,21025,61009,82369,180625,227529,423801,511225,
%T A014769 855625,1002001,1555009,1782225,2614689,2948089,4141225,4609609,
%U A014769 6255001,6890625,9090225,9928801,12794929,13875625,17530969,18896409,23474025,25170289,30813601
%N A014769 Squares of odd pentagonal numbers.
%H A014769 Colin Barker, <a href="/A014769/b014769.txt">Table of n, a(n) for n = 0..1000</a>
%H A014769 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (1,4,-4,-6,6,4,-4,-1,1).
%F A014769 a(n) = A014632(n)^2. - _Sean A. Irvine_, Nov 20 2018
%F A014769 From _Colin Barker_, Nov 20 2018: (Start)
%F A014769 G.f.: (1 + 24*x + 1196*x^2 + 1280*x^3 + 6294*x^4 + 1976*x^5 + 2828*x^6 + 176*x^7 + 49*x^8) / ((1 - x)^5*(1 + x)^4).
%F A014769 a(n) = a(n-1) + 4*a(n-2) - 4*a(n-3) - 6*a(n-4) + 6*a(n-5) + 4*a(n-6) - 4*a(n-7) - a(n-8) + a(n-9) for n>8.
%F A014769 a(n) = 36*n^4 + 60*n^3 + 37*n^2 + 10*n + 1 for n even.
%F A014769 a(n) = 36*n^4 - 12*n^3 + n^2 for n odd.
%F A014769 (End)
%t A014769 Select[Table[PolygonalNumber[5,n]^2, {n,0, 61}],OddQ] (* _James C. McMahon_, Dec 24 2023 *)
%t A014769 Select[PolygonalNumber[5,Range[70]],OddQ]^2 (* or *) LinearRecurrence[{1,4,-4,-6,6,4,-4,-1,1},{1,25,1225,2601,13689,21025,61009,82369,180625},40] (* _Harvey P. Dale_, Apr 07 2025 *)
%o A014769 (PARI) Vec((1 + 24*x + 1196*x^2 + 1280*x^3 + 6294*x^4 + 1976*x^5 + 2828*x^6 + 176*x^7 + 49*x^8) / ((1 - x)^5*(1 + x)^4) + O(x^40)) \\ _Colin Barker_, Nov 20 2018
%Y A014769 Cf. A014632.
%Y A014769 Odd terms of A100255.
%K A014769 nonn,easy
%O A014769 0,2
%A A014769 _Mohammad K. Azarian_
%E A014769 More terms from Scott Lindhurst (ScottL(AT)alumni.princeton.edu)