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 A273365 #17 Apr 19 2019 10:09:08
%S A273365 0,6,14,32,48,78,102,144,176,230,270,336,384,462,518,608,672,774,846,
%T A273365 960,1040,1166,1254,1392,1488,1638,1742,1904,2016,2190,2310,2496,2624,
%U A273365 2822,2958,3168,3312,3534,3686,3920,4080,4326,4494
%N A273365 Numbers k such that 10*k+4 is a perfect square.
%H A273365 G. C. Greubel, <a href="/A273365/b273365.txt">Table of n, a(n) for n = 0..1000</a>
%H A273365 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,2,-2,-1,1).
%F A273365 a(2n) = 10*n^2 + 4*n, n>=0.
%F A273365 a(2n-1) = 10*n^2 - 4*n, n>=1.
%F A273365 G.f.: 2*x*(3*x^2+4x+3)/((1-x)^3*(1+x)^2).
%F A273365 From _G. C. Greubel_, May 21 2016: (Start)
%F A273365 E.g.f.: (1/2)*((5*x^2 + 11*x)*cosh(x) + (5*x^2 + 9*x + 1)*sinh(x)).
%F A273365 a(n) = a(n-1) + 2*a(n-2) - 2*a(n-3) - a(n-4) + a(n-5). (End)
%t A273365 LinearRecurrence[{1, 2, -2, -1, 1}, {0, 6, 14, 32, 48}, 50] (* _G. C. Greubel_, May 21 2016 *)
%t A273365 Select[Range[0,5000],IntegerQ[Sqrt[10#+4]]&] (* _Harvey P. Dale_, Apr 19 2019 *)
%o A273365 (PARI) is(n)=issquare(10*n+4) \\ _Charles R Greathouse IV_, Jan 31 2017
%Y A273365 Cf. A132356, A273366, A273367, A273368.
%Y A273365 Cf. A033583 (perfect squares ending in 0 in base 10 with final 0 removed).
%K A273365 nonn,easy
%O A273365 0,2
%A A273365 _Nathan Fox_, _Brooke Logan_, and _N. J. A. Sloane_, May 20 2016