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 A051048 #12 Feb 16 2025 08:32:41
%S A051048 2,5,31,449,6271,87361,1216799,16947841,236052991,3287794049,
%T A051048 45793063711,637815097921,8883618307199,123732841202881,
%U A051048 1723376158533151,24003533378261249,334326091137124351
%N A051048 Sqrt[a(n)a(n+1)+1] of A051047.
%H A051048 Z. Franusic, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL13/Franusic/franusic4.html">On the Extension of the Diophantine Pair {1,3} in Z[surd d]</a>, J. Int. Seq. 13 (2010) # 10.9.6
%H A051048 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DiophantusProperty.html">Diophantus Property.</a>
%H A051048 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (15,-15,1).
%F A051048 G.f.: x(-4x^4+57x^3-14x^2-25x+2)/[(1-x)(1-14x+x^2)].
%Y A051048 Cf. A051047.
%K A051048 nonn
%O A051048 1,1
%A A051048 _Eric W. Weisstein_