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 A238940 #13 Jan 28 2023 14:00:50 %S A238940 1,4,16,64,256,16384,65536,262144,16777216,268435456,4294967296, %T A238940 17179869184,68719476736,4722366482869645213696, %U A238940 75557863725914323419136,77371252455336267181195264 %N A238940 Powers of 4 without the digit '0' in their decimal expansion. %C A238940 Conjectured to be finite and complete. See the OEIS wiki page for further information, references and links. %H A238940 M. F. Hasler, <a href="https://oeis.org/wiki/Zeroless_powers">Zeroless powers</a>, OEIS Wiki, Mar 07 2014 %F A238940 a(n)=4^A030701(n). %t A238940 Select[4^Range[0,50],DigitCount[#,10,0]==0&] (* _Harvey P. Dale_, Aug 31 2021 *) %o A238940 (PARI) for(n=0,99,vecmin(digits(4^n))&& print1(4^n",")) %Y A238940 For the zeroless numbers (powers x^n), see A238938, A238939, A238940, A195948, A238936, A195908, A195946, A195945, A195942, A195943. %Y A238940 For the corresponding exponents, see A007377, A008839, A030700, A030701, A030702, A030703, A030704, A030705, A030706, A195944. %Y A238940 For other related sequences, see A052382, A027870, A102483. %K A238940 nonn,base %O A238940 1,2 %A A238940 _M. F. Hasler_, Mar 07 2014 %E A238940 Keyword:fini removed by _Jianing Song_, Jan 28 2023 as finiteness is only conjectured.