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 A061297 #20 Mar 09 2023 12:59:30
%S A061297 1,2,4,8,14,32,39,114,166,266,421,1608,1005,3980,6894,4206,8666,40904,
%T A061297 49559,315478,162321,79180,269878,1647124,937553,1810092,8445654,
%U A061297 7791356,3978238,33071544,19578861,283536170,327438714,117635956,742042967,154748984,88779589,1532487536,10514107742,3761632498
%N A061297 a(n) = Sum_{ r = 0 to n} L(n,r), where L(n,r) (A067049) = lcm(n, n-1, n-2, ..., n-r+1)/lcm(1, 2, 3, ..., r).
%C A061297 The following sequences all appear to have the same parity: A003071, A029886, A061297, A092524, A093431, A102393, A104258, A122248, A128975. - _Jeremy Gardiner_, Dec 28 2008
%D A061297 Amarnath Murthy, Some Notions On Least Common Multiples, Smarandache Notions Journal, Vol. 12, No. 1-2-3, Spring 2001.
%H A061297 Tanya Khovanova, <a href="http://arxiv.org/abs/1410.2193">There are no coincidences</a>, arXiv preprint 1410.2193 [math.CO], 2014.
%e A061297 a(0) = 1, a(4) = 14: we have L(4,0) = 1, L(4,1) = 4, L(4,2) = 6, L(4,3) = 2, L(4,4) = 1. For r = 0 to 4, sigma {L(4,r)}= 1 + 4 + 6 + 2 + 1 = 14.
%o A061297 (PARI) tlcm(n, r) = {nt = 1; for (k = n-r+1, n, nt = lcm(nt, k);); dt = 1; for (k = 1, r, dt = lcm(dt, k);); return (nt/dt);}
%o A061297 a(n) = sum(r = 0, n , tlcm(n, r)); \\ _Michel Marcus_, Sep 14 2013
%Y A061297 Row sums of A067049.
%K A061297 nonn,easy
%O A061297 0,2
%A A061297 _Amarnath Murthy_, Apr 26 2001