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 A085597 #24 Jul 19 2021 19:25:53 %S A085597 1,11,15,33,39,71,91,173,175,179,335,3337,5597,7353 %N A085597 Numbers k such that k and k^3 use only odd digits. %C A085597 Numbers k such that k^3 uses only odd digits are in A030099. %C A085597 No other terms below 10^16. The sequence is likely finite. - _Max Alekseyev_, Oct 17 2017 %C A085597 a(15) > 10^19, if it exists. - _Giovanni Resta_, Mar 13 2020 %e A085597 15 is a term because both 15 and 15^3=3375 use only odd digits. %t A085597 Select[Range[10000],And@@OddQ[Join[IntegerDigits[#],IntegerDigits[ #^3]]]&] (* _Harvey P. Dale_, May 15 2012 *) %o A085597 (PARI) isoddd(n) = #select(x->((x%2) == 0), digits(n)) == 0; %o A085597 isok(n) = isoddd(n) && isoddd(n^3); \\ _Michel Marcus_, Dec 03 2016 %Y A085597 Cf. A030099. %K A085597 nonn,base,more %O A085597 1,2 %A A085597 _Zak Seidov_, Jul 06 2003