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 A054774 #11 Feb 18 2021 02:34:41
%S A054774 2,5,8,20,32,50,80,125,128,200,320,500,512,800,1250,1280,2000,2048,
%T A054774 3125,3200,5000,5120,8000,8192,12500,12800,20000,20480,31250,32000,
%U A054774 32768,50000,51200,78125,80000,81920,125000,128000,131072,200000
%N A054774 Numbers of the form 2^i*5^j where i+j is odd.
%C A054774 m is in the sequence iff m/10 is already in the sequence or m is an odd power of 2 or 5.
%H A054774 Amiram Eldar, <a href="/A054774/b054774.txt">Table of n, a(n) for n = 1..10000</a>
%F A054774 Sum_{n>=1} 1/a(n) = 35/36. - _Amiram Eldar_, Feb 18 2021
%t A054774 max = 200000; Reap[Do[k = 2^i*5^j; If[k <= max && OddQ[i + j], Sow[k]], {i, 0, Log[2, max] // Ceiling}, {j, 0, Log[5, max] // Ceiling}]][[2, 1]] // Union (* _Amiram Eldar_, Feb 18 2021 after _Jean-François Alcover_ at A036667 *)
%Y A054774 Intersection of A026424 and A003592.
%Y A054774 Cf. A004171, A013710.
%K A054774 easy,nonn
%O A054774 1,1
%A A054774 _Henry Bottomley_, May 19 2000