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 A024853 #8 May 15 2025 12:08:49 %S A024853 3,4,13,16,34,40,70,80,125,140,203,224,308,336,444,480,615,660,825, %T A024853 880,1078,1144,1378,1456,1729,1820,2135,2240,2600,2720,3128,3264,3723, %U A024853 3876,4389,4560,5130,5320,5950,6160,6853,7084,7843,8096,8924,9200,10100,10400 %N A024853 a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = (natural numbers >= 2). %F A024853 a(n) = m * (m+1) * (3*n+5-2*m) / 6 where m = floor(n/2). - _Sean A. Irvine_, Jul 26 2019 %Y A024853 Apart from offset the same as A023857. %K A024853 nonn,easy %O A024853 2,1 %A A024853 _Clark Kimberling_