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 A129994 #12 Nov 03 2017 03:44:45
%S A129994 1,2,1,2,4,1,2,6,6,1,2,8,12,8,1,2,10,20,20,10,1,2,12,30,40,30,12,1,2,
%T A129994 14,42,70,70,42,14,1,2,16,56,112,140,112,56,16,1,2,18,72,168,252,252,
%U A129994 168,72,18,1
%N A129994 Triangle read by rows: 2*A007318 - I.
%C A129994 Row sums = (1, 3, 7, 15, 31, ...).
%F A129994 Let Pascal's triangle A007318 = P, then this is 2*P - I, I = Identity matrix.
%e A129994 First few rows of the triangle are:
%e A129994 1;
%e A129994 2, 1;
%e A129994 2, 4, 1;
%e A129994 2, 6, 6, 1;
%e A129994 2, 8, 12, 8, 1;
%e A129994 2, 10, 20, 20, 10, 1;
%e A129994 2, 12, 30, 40, 30, 12, 1;
%e A129994 ...
%t A129994 Table[2 Binomial[n, k] - Boole[k == n], {n, 0, 9}, {k, 0, n}] // Flatten (* _Michael De Vlieger_, Nov 02 2017 *)
%Y A129994 Cf. A007318.
%K A129994 nonn,tabl
%O A129994 0,2
%A A129994 _Gary W. Adamson_, Jun 15 2007
%E A129994 Name corrected by _Peter Bala_, Nov 02 2017