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 A378557 #8 Dec 12 2024 23:32:27 %S A378557 1,9,27,81,729,2187,6561,59049,177147,4782969,1162261467, %T A378557 7625597484987,22876792454961,16677181699666569,12157665459056928801, %U A378557 717897987691852588770249,174449211009120179071170507,11972515182562019788602740026717047105681 %N A378557 Powers of 3 that do not contain the digit 3. %C A378557 Any additional terms have exponent at least 10^5. %F A378557 a(n) = 3^A131629(n). %t A378557 Select[3^Range[0,100000],Not[MemberQ[IntegerDigits[#],3]]&] %Y A378557 Cf. A000244, A131629. %K A378557 nonn,base,fini %O A378557 1,2 %A A378557 _Erich Friedman_, Nov 30 2024