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 A045050 #13 May 28 2023 01:36:34 %S A045050 522,546,552,642,648,672,1066,1162,1186,1192,1546,1570,1576,1666,1672, %T A045050 1696,2074,2086,2089,2091,2094,2106,2122,2146,2152,2182,2185,2187, %U A045050 2190,2194,2200,2209,2211,2212,2220,2226,2232,2250 %N A045050 Numbers whose base-4 representation contains exactly two 0's and three 2's. %H A045050 Vincenzo Librandi, <a href="/A045050/b045050.txt">Table of n, a(n) for n = 1..4000</a> %t A045050 Select[Range[7000], DigitCount[#, 4, 0] == 2 && DigitCount[#, 4, 2] == 3 &] (* _Vincenzo Librandi_, Sep 21 2016 *) %Y A045050 Cf. A007090. %K A045050 nonn,base %O A045050 1,1 %A A045050 _Clark Kimberling_