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 A018002 #10 Sep 08 2022 08:44:44
%S A018002 1,3,5,9,19,39,81,169,351,729,1517,3155,6561,13648,28388,59049,122827,
%T A018002 255491,531441,1105442,2299412,4782969,9948977,20694705,43046721,
%U A018002 89540788,186252345,387420489,805867092,1676271102,3486784401,7252803827,15086439913,31381059609
%N A018002 Powers of cube root of 9 rounded up.
%H A018002 Vincenzo Librandi, <a href="/A018002/b018002.txt">Table of n, a(n) for n = 0..200</a>
%t A018002 Table[Ceiling[9^(n/3)], {n, 0, 40}] (* _Vincenzo Librandi_, Jan 09 2014 *)
%o A018002 (Magma) [Ceiling(9^(n/3)): n in [0..50]]; // _Vincenzo Librandi_, Jan 09 2014
%Y A018002 Cf. powers of cube root of k ceiling up: A017981 (k=2), A017984 (k=3), A017987 (k=4), A017990 (k=5), A017993 (k=6), A017996 (k=7), this sequence (k=9), A018005 (k=10), A018008 (k=11), A018011 (k=12), A018014 (k=13), A018017 (k=14), A018020 (k=15), A018023 (k=16), A018026 (k=17), A018029 (k=18), A018032 (k=19), A018035 (k=20), A018038 (k=21), A018041 (k=22), A018044 (k=23), A018047 (k=24).
%K A018002 nonn
%O A018002 0,2
%A A018002 _N. J. A. Sloane_
%E A018002 More terms from _Vincenzo Librandi_, Jan 09 2014