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 A023735 #13 Mar 24 2021 18:24:53 %S A023735 18,43,68,78,83,88,90,91,92,94,98,118,143,168,193,203,208,213,215,216, %T A023735 217,219,223,243,268,293,318,328,333,338,340,341,342,344,348,368,378, %U A023735 383,388,390,391,392,394,398,403,408,413,415,416,417,419,423 %N A023735 Numbers with exactly 2 3's in their base-5 expansion. %H A023735 Nathaniel Johnston, <a href="/A023735/b023735.txt">Table of n, a(n) for n = 1..10000</a> %p A023735 seq(`if`(numboccur(3,convert(n,base,5))=2,n,NULL),n=0..450); # _Nathaniel Johnston_, Jun 27 2011 %t A023735 Select[ Range[ 450 ], (Count[ IntegerDigits[ #, 5 ], 3 ]==2)& ] %t A023735 Select[Range[500],DigitCount[#,5,3]==2&] (* _Harvey P. Dale_, Mar 24 2021 *) %Y A023735 Cf. A023733, A023734. %K A023735 nonn,base,easy %O A023735 1,1 %A A023735 _Olivier Gérard_