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 A221946 #10 Sep 08 2022 08:46:04
%S A221946 1,3,9,26,69,183,485,1283,3395,8983,23768,62886,166380,440202,1164665,
%T A221946 3081415,8152659,21569910,57068618,150989371,399480328,1056925602,
%U A221946 2796362297,7398479214,19574536080,51789354498,137021752562,362525481486,959152267937,2537678370405,6714065875561,17763748592841
%N A221946 a(n) = floor(sqrt(2*7^n)).
%H A221946 G. C. Greubel, <a href="/A221946/b221946.txt">Table of n, a(n) for n = 0..1000</a>
%t A221946 Table[Floor[Sqrt[2*7^n]], {n, 0, 50}] (* _G. C. Greubel_, Jan 26 2018 *)
%o A221946 (PARI) a(n)=sqrtint(2*7^n) \\ _Charles R Greathouse IV_, Apr 18 2013
%o A221946 (Magma) [Floor(Sqrt(2*7^n)): n in [0..50]]; // _G. C. Greubel_, Jan 26 2018
%Y A221946 Cf. A017910, A017913, A017919, A114183, A221718, A221942-A221946.
%K A221946 nonn
%O A221946 0,2
%A A221946 _N. J. A. Sloane_, Feb 01 2013