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 A201125 #11 Dec 07 2022 08:57:50
%S A201125 1,4,7,7,28,23,92,7,28,112,448,1792,7168,5503,22012,88048,166831,
%T A201125 296599,444943,296863,1187452,4749808,7135951,4817239,19268956,
%U A201125 77075824,118490767,94338007,377352028,1509408112,3000631951,5928526807,11566105231,21968416927,39281659711,59942622847,45402459391,181609837564,726439350256
%N A201125 Differences between odd powers of 2 and the next smaller square.
%H A201125 Hugo Pfoertner, <a href="/A201125/b201125.txt">Table of n, a(n) for n = 1..500</a>
%F A201125 a(n) = 2^(2*n-1) - floor(sqrt(2^(2*n-1)))^2.
%F A201125 Apparently a(n) = A095803(n)/4 for n >= 1. - _Hugo Pfoertner_, Dec 07 2022
%e A201125 a(1)=2^1-1^1=1, a(2)=2^3-2^2=4, a(3)=2^5-5^2=32-25=7
%t A201125 Table[2^n-Floor[Sqrt[2^n]]^2,{n,1,81,2}] (* _Harvey P. Dale_, Feb 25 2018 *)
%Y A201125 Cf. A051213, A095803.
%K A201125 nonn
%O A201125 1,2
%A A201125 _Hugo Pfoertner_, Nov 27 2011