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 A257825 #9 Sep 08 2022 08:46:12
%S A257825 2257,2849,21941,27713,604765,763865,16669573,21054961,162316669,
%T A257825 205018517,4474051285,5651073085,123321498797,155764598629,
%U A257825 1200818695321,1516726961053,33099030801665,41806637918965,912332431430633,1152346479602381,8883656545668089
%N A257825 Positive integers whose square is the sum of 74 consecutive squares.
%C A257825 Positive integers x in the solutions to 2*x^2-148*y^2-10804*y-264698 = 0.
%H A257825 Colin Barker, <a href="/A257825/b257825.txt">Table of n, a(n) for n = 1..1000</a>
%H A257825 <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,7398,0,0,0,0,0,-1).
%F A257825 a(n) = 7398*a(n-6)-a(n-12).
%F A257825 G.f.: -37*x*(5*x^11+5*x^10+61*x^9+77*x^8+593*x^7+749*x^6-20645*x^5-16345*x^4-749*x^3-593*x^2-77*x-61) / ((x^6-86*x^3-1)*(x^6+86*x^3-1)).
%e A257825 2257 is in the sequence because 2257^2 = 5094049 = 225^2+226^2+...+298^2.
%t A257825 LinearRecurrence[{0, 0, 0, 0, 0, 7398, 0, 0, 0, 0, 0, -1}, {2257, 2849, 21941, 27713, 604765, 763865, 16669573, 21054961, 162316669, 205018517, 4474051285, 5651073085}, 40] (* _Vincenzo Librandi_, May 11 2015 *)
%o A257825 (PARI) Vec(-37*x*(5*x^11+5*x^10+61*x^9+77*x^8+593*x^7+749*x^6-20645*x^5-16345*x^4-749*x^3-593*x^2-77*x-61) / ((x^6-86*x^3-1)*(x^6+86*x^3-1)) + O(x^100))
%o A257825 (Magma) I:=[2257,2849,21941,27713,604765,763865,16669573, 21054961,162316669,205018517,4474051285,5651073085]; [n le 12 select I[n] else 7398*Self(n-6)-Self(n-12): n in [1..40]]; // _Vincenzo Librandi_, May 11 2015
%Y A257825 Cf. A001653, A180274, A218395, A257761, A257765, A257767, A257780, A257781, A257823, A257824, A257826-A257828.
%K A257825 nonn,easy
%O A257825 1,1
%A A257825 _Colin Barker_, May 10 2015