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 A134478 #23 Mar 26 2022 11:10:56
%S A134478 1,1,2,2,3,4,3,4,5,6,4,5,6,7,8,5,6,7,8,9,10,6,7,8,9,10,11,12,7,8,9,10,
%T A134478 11,12,13,14,8,9,10,11,12,13,14,15,16,9,10,11,12,13,14,15,16,17,18
%N A134478 Triangle read by rows, T(0,0) = 1; n-th row = (n+1) terms of n, n+1, n+2, ...
%C A134478 Apart from the irregular choice of T(0,0) the same as A051162. - _R. J. Mathar_, Mar 28 2012
%H A134478 G. C. Greubel, <a href="/A134478/b134478.txt">Table of n, a(n) for the first 100 rows, flattened</a>
%e A134478 First few rows of the triangle:
%e A134478 1;
%e A134478 1, 2;
%e A134478 2, 3, 4;
%e A134478 3, 4, 5, 6;
%e A134478 4, 5, 6, 7, 8;
%e A134478 5, 6, 7, 8, 9, 10;
%e A134478 6, 7, 8, 9, 10, 11, 12;
%e A134478 7, 8, 9, 10, 11, 12, 13, 14;
%e A134478 ...
%t A134478 Join[{1},Flatten[Table[Range[n,2n],{n,10}]]] (* _Harvey P. Dale_, Nov 21 2014 *)
%o A134478 (PARI) concat([1], for(n=1,10, for(k=0,n, print1(n+k, ", ")))) \\ _G. C. Greubel_, Sep 24 2017
%Y A134478 Cf. A051162, A134479 (row sums), A126804 (row products).
%K A134478 nonn,less,tabl
%O A134478 0,3
%A A134478 _Gary W. Adamson_, Oct 27 2007