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 A212456 #23 Jan 20 2024 11:27:18
%S A212456 3,10,19,29,40,52,63,76,88,102,115,129,142,156,171,185,200,215,230,
%T A212456 245,261,276,292,307,323,339,355,372,388,404,421,438,454,471,488,505,
%U A212456 522,539,557,574,591,609,626,644,662,679
%N A212456 a(n) = floor(3n*log(3n)).
%H A212456 Vincenzo Librandi, <a href="/A212456/b212456.txt">Table of n, a(n) for n = 1..1000</a>
%t A212456 Table[Floor[3*n*Log[3*n]], {n, 60}] (* _Vincenzo Librandi_, Feb 13 2013 *)
%o A212456 (Derive) PROG(y := [], x := 100, LOOP(IF(x = 0, RETURN y), y := ADJOIN(FLOOR(3·x·LOG(3·x)), y), x := x - 1))
%o A212456 (Magma) [Floor(3*n*Log(3*n)): n in [1..80]]; // _Vincenzo Librandi_, Feb 13 2013
%o A212456 (PARI) a(n)=3*n*log(3*n)\1 \\ _Charles R Greathouse IV_, Sep 04 2015
%Y A212456 Cf. A050502, A050504, A212455, A212457, A212458, A212459, A212460, A212461, A212462.
%K A212456 easy,nonn
%O A212456 1,1
%A A212456 _Mohammad K. Azarian_, May 31 2012