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 A144113 #10 Feb 01 2025 08:45:06
%S A144113 1,2,1,3,1,2,4,1,1,3,5,1,1,1,4,6,1,1,1,1,5,7,1,1,1,1,1,6,8,1,1,1,1,1,
%T A144113 1,7,9,1,1,1,1,1,1,1,8,10,1,1,1,1,1,1,1,1,9,11,1,1,1,1,1,1,1,1,1,10,
%U A144113 12,1,1,1,1,1,1,1,1,1,1,11,13,1,1,1,1,1,1,1,1,1,1,1,12,14,1,1,1,1,1,1,1,1,1
%N A144113 Weight array W={w(i,j)} of the natural number array A038722.
%C A144113 In general, let w(i,j) be the weight of the unit square labeled by its northeast vertex (i,j) and for each (m,n), define S(m,n) = Sum_{i=1..m} Sum_{j=1..n} w(i,j).
%C A144113 Then S(m,n) is the weight of the rectangle [0,m]x[0,n]. We call W the weight array of S and we call S the accumulation array of W. For the case at hand, S is the array of natural numbers having the following antidiagonals: (1), then (3,2), then (6,5,4), then (10,9,8,7) and so on.
%F A144113 row 1: A000027
%F A144113 row n: n-1 followed by A000012, for n>1.
%e A144113 S(2,4)=1+1+2+3+2+1+1+1=14.
%Y A144113 Cf. A000012, A000027, A144112.
%K A144113 nonn,tabl
%O A144113 1,2
%A A144113 _Clark Kimberling_, Sep 11 2008