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 A039284 #18 Oct 27 2021 09:31:33 %S A039284 10,27,35,51,53,54,55,65,70,77,85,102,110,132,136,138,139,142,147,152, %T A039284 160,176,178,179,180,190,195,202,210,227,235,252,256,258,259,260,266, %U A039284 268,269,271,273,274,276,278,279,280,290,295,300,326,328,329,330,340 %N A039284 Numbers whose base-5 representation has the same nonzero number of 0's and 2's. %t A039284 Select[Range[400],DigitCount[#,5,0]==DigitCount[#,5,2]>0&] (* _Harvey P. Dale_, Oct 03 2014 *) %o A039284 (Python) %o A039284 from sympy.ntheory import count_digits %o A039284 def ok(n): c = count_digits(n, b=5); return c[0] == c[2] > 0 %o A039284 print([k for k in range(341) if ok(k)]) # _Michael S. Branicky_, Oct 27 2021 %Y A039284 Cf. A007091. %Y A039284 Supersequence of A045177. %K A039284 nonn,base,easy %O A039284 1,1 %A A039284 _Olivier Gérard_