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 A109050 #28 Sep 08 2023 07:33:13
%S A109050 0,9,18,9,36,45,18,63,72,9,90,99,36,117,126,45,144,153,18,171,180,63,
%T A109050 198,207,72,225,234,27,252,261,90,279,288,99,306,315,36,333,342,117,
%U A109050 360,369,126,387,396,45,414,423,144,441,450,153,468,477,54,495,504
%N A109050 a(n) = lcm(n, 9).
%H A109050 Amiram Eldar, <a href="/A109050/b109050.txt">Table of n, a(n) for n = 0..10000</a>
%H A109050 <a href="/index/Rec#order_18">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0, 0,-1).
%H A109050 <a href="/index/Lc#lcm">Index entries for sequences related to lcm's</a>.
%F A109050 a(n) = n*9/gcd(n, 9).
%F A109050 a(n) = 9*n/A109012(n) = 9*A106610(n). - _R. J. Mathar_, Apr 18 2011
%F A109050 Sum_{k=1..n} a(k) ~ (61/18) * n^2. - _Amiram Eldar_, Nov 26 2022
%F A109050 Sum_{n>=1} (-1)^(n+1)/a(n) = 7*log(2)/27. - _Amiram Eldar_, Sep 08 2023
%t A109050 LCM[9,Range[0,60]] (* _Harvey P. Dale_, Aug 21 2021 *)
%o A109050 (Sage) [lcm(n,9)for n in range(0, 57)] # _Zerinvary Lajos_, Jun 09 2009
%o A109050 (Magma) [Lcm(n,9): n in [0..100]]; // _Vincenzo Librandi_, Apr 18 2011
%Y A109050 Cf. A106610, A109012, A109042.
%K A109050 nonn,easy
%O A109050 0,2
%A A109050 _Mitch Harris_, Jun 18 2005