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 A017983 #18 Jul 08 2025 06:20:47
%S A017983 1,1,2,3,4,6,9,13,19,27,39,56,81,117,168,243,350,505,729,1051,1516,
%T A017983 2187,3154,4549,6561,9463,13647,19683,28388,40942,59049,85163,122827,
%U A017983 177147,255490,368481,531441,766471,1105442,1594323,2299412,3316325,4782969,6898235
%N A017983 Powers of cube root of 3 rounded to nearest integer.
%H A017983 Vincenzo Librandi, <a href="/A017983/b017983.txt">Table of n, a(n) for n = 0..200</a>
%t A017983 Table[Round[3^(n/3)], {n, 0, 50}] (* _Vincenzo Librandi_, Jan 07 2014 *)
%t A017983 Round[CubeRoot[3]^Range[0,50]] (* _Harvey P. Dale_, Jul 21 2023 *)
%o A017983 (Magma) [Round(3^(n/3)): n in [0..50]]; // _Vincenzo Librandi_, Jan 07 2014
%o A017983 (Python)
%o A017983 from sympy import integer_nthroot
%o A017983 def A017983(n): return -integer_nthroot(m:=3**n,3)[0]+integer_nthroot(m<<3,3)[0] # _Chai Wah Wu_, Jun 18 2024
%Y A017983 Cf. powers of cube root of k rounded up: A017980 (k=2), this sequence (k=3), A017986 (k=4), A017989 (k=5), A017992 (k=6), A017995 (k=7), A018001 (k=9), A018004 (k=10), A018007 (k=11), A018010 (k=12), A018013 (k=13), A018016 (k=14), A018019 (k=15), A018022 (k=16), A018025 (k=17), A018028 (k=18), A018031 (k=19), A018034 (k=20), A018037 (k=21), A018040 (k=22), A018043 (k=23), A018046 (k=24).
%K A017983 nonn
%O A017983 0,3
%A A017983 _N. J. A. Sloane_
%E A017983 More terms from _Vincenzo Librandi_, Jan 07 2014