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 A192121 #14 Nov 16 2021 13:34:01
%S A192121 0,4,6,7,32,48,56,60,62,63,256,384,448,480,496,504,508,510,511,2048,
%T A192121 3072,3584,3840,3968,4032,4064,4080,4088,4092,4094,4095,16384,24576,
%U A192121 28672,30720,31744,32256,32512,32640,32704,32736,32752,32760,32764,32766,32767
%N A192121 Monotonic ordering of nonnegative differences 8^i - 2^j, for 40 >= i >= 0, j >= 0.
%H A192121 Nathaniel Johnston, <a href="/A192121/b192121.txt">Table of n, a(n) for n = 1..2461</a> [truncated to 8^40-1 by _Georg Fischer_, Nov 16 2021]
%p A192121 A192121:={}: for i from 0 to 5 do for j from 0 to 3*i do A192121 := A192121 union {8^i-2^j}: od: od: op(A192121); # _Nathaniel Johnston_, Jun 23 2011
%t A192121 c = 8; d = 2; t[i_, j_] := c^i - d^j;
%t A192121 u = Table[t[i, j], {i, 0, 40}, {j, 0, i*Log[d, c]}];
%t A192121 v = Union[Flatten[u ]]
%Y A192121 Cf. A192110, A192120.
%K A192121 nonn,easy,fini
%O A192121 1,2
%A A192121 _Clark Kimberling_, Jun 23 2011