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 A134464 #8 Mar 25 2022 00:33:28
%S A134464 1,2,4,3,5,8,4,6,9,13,5,7,10,14,19,6,8,11,15,20,26,7,9,12,16,21,27,34,
%T A134464 8,10,13,17,22,28,35,43,9,11,14,18,23,29,36,44,53,10,12,15,19,24,30,
%U A134464 37,45,54,64
%N A134464 (A127648 * A000012 + A000012 * A127773) - A000012.
%C A134464 Row sums = A134465: (1, 6, 16, 32, 55, 86, ...).
%H A134464 Harvey P. Dale, <a href="/A134464/b134464.txt">Table of n, a(n) for n = 1..1000</a>
%F A134464 (A127648 * A000012 * A000012 * A127773) - A000012, as infinite lower triangular matrices.
%e A134464 First few rows of the triangle:
%e A134464 1;
%e A134464 2, 4;
%e A134464 3, 5, 8;
%e A134464 4, 6, 9, 13;
%e A134464 5, 7, 10, 14, 19;
%e A134464 6, 8, 11, 15, 20, 26;
%e A134464 7, 9, 12, 16, 21, 27, 34;
%e A134464 ...
%t A134464 Flatten[Table[RecurrenceTable[{a[1]==i,a[n]==a[n-1]+n},a,{n,i}],{i,10}]] (* _Harvey P. Dale_, Nov 12 2013 *)
%Y A134464 Cf. A127648, A127773, A134465.
%K A134464 nonn,tabl
%O A134464 1,2
%A A134464 _Gary W. Adamson_, Oct 26 2007