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 A030705 #35 Feb 16 2025 08:32:35 %S A030705 0,1,2,3,4,6,7,12,13,14,17,34 %N A030705 Numbers k such that the decimal expansion of 9^k contains no zeros (probably finite). %C A030705 Integers in A030700 / 2. - _M. F. Hasler_, Mar 07 2014 %C A030705 No more terms <= 10^5. - _Georg Fischer_, Mar 12 2020 %H A030705 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Zero.html">Zero</a> %t A030705 Reap[For[n = 0, n < 100, n++, If[FreeQ[IntegerDigits[9^n], 0], Sow[n]]]][[2, 1]] (* _Jean-François Alcover_, Oct 04 2017 *) %o A030705 (PARI) select( is(n)=vecmin(digits(9^n)), [0..39]) \\ _M. F. Hasler_, Mar 07 2014 %o A030705 (Magma) [n: n in [0..500] | not 0 in Intseq(9^n)]; // _Vincenzo Librandi_, Mar 08 2014 %Y A030705 Cf. A007377 (analog for 2^n), A030700 (3), A030701 (4), A008839 (5), A030702 (6), A030703 and A195908 (7), A030704 (8), A030706 and A195946 (11), A195944 and A195945 (13); A195942, A195943. %Y A030705 This is row 0 of A305929. %Y A030705 Cf. A035064. %K A030705 nonn,base %O A030705 1,3 %A A030705 _Eric W. Weisstein_ %E A030705 Offset changed to 1 and initial 0 added by _M. F. Hasler_, Mar 07 2014 %E A030705 Removed keyword "fini" (as in A035064) since it is only a conjecture that this sequence contains only finitely many terms. - _Georg Fischer_, Mar 12 2020