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 A018018 #13 Sep 08 2022 08:44:44
%S A018018 1,2,6,15,36,91,225,554,1368,3375,8323,20527,50625,124851,307911,
%T A018018 759375,1872779,4618672,11390625,28091696,69280082,170859375,
%U A018018 421375453,1039201231,2562890625,6320631804,15588018473,38443359375,94809477068,233820277107
%N A018018 Powers of cube root of 15 rounded down.
%H A018018 Vincenzo Librandi, <a href="/A018018/b018018.txt">Table of n, a(n) for n = 0..200</a>
%t A018018 Table[Floor[15^(n/3)], {n, 0, 40}] (* _Vincenzo Librandi_, Jan 06 2014 *)
%t A018018 Floor[Surd[15,3]^Range[0,40]] (* _Harvey P. Dale_, Jun 21 2017 *)
%o A018018 (Magma) [Floor(15^(n/3)): n in [0..40]]; // _Vincenzo Librandi_, Jan 06 2014
%Y A018018 Cf. powers of cube root of k rounded down: A017979 (k=2), A017982 (k=3), A017985 (k=4), A017988 (k=5), A017991 (k=6), A017994 (k=7), A018000 (k=9), A018003 (k=10), A018006 (k=11), A018009 (k=12), A018012 (k=13), A018015 (k=14), this sequence (k=15), A018021 (k=16), A018024 (k=17), A018027 (k=18), A018030 (k=19), A018033 (k=20), A018036 (k=21), A018039 (k=22), A018042 (k=23), A018045 (k=24).
%K A018018 nonn
%O A018018 0,2
%A A018018 _N. J. A. Sloane_
%E A018018 More terms from _Vincenzo Librandi_, Jan 06 2014