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 A127253 #7 Aug 04 2023 04:35:43 %S A127253 1,0,1,-1,0,1,0,0,0,1,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0, %T A127253 0,1,0,0,0,0,0,0,-1,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0, %U A127253 0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1 %N A127253 Product of number triangles A127243 and A127248. %C A127253 Rows containing -1 entries are indexed by twice the odious numbers given by A091855. %e A127253 Triangle begins: %e A127253 1; %e A127253 0, 1; %e A127253 -1, 0, 1; %e A127253 0, 0, 0, 1; %e A127253 0, 0, 0, 0, 1; %e A127253 0, 0, 0, 0, 0, 1; %e A127253 0, 0, 0, 0, 0, 0, 1; %e A127253 0, 0, 0, 0, 0, 0, 0, 1; %e A127253 0, 0, 0, 0, 0, 0, -1, 0, 1; %e A127253 0, 0, 0, 0, 0, 0, 0, 0, 0, 1; %e A127253 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1; %e A127253 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1; %e A127253 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1; %e A127253 ... %t A127253 T1[n_, k_] := SeriesCoefficient[(1 + ThueMorse[1 + k]*x)*x^k, {x, 0, n}]; (* A127243 *) %t A127253 T2[n_, k_] := SeriesCoefficient[(1 - ThueMorse[1 + k]*x)*x^k, {x, 0, n}]; (* A127248 *) %t A127253 T[n_, k_] := Sum[T2[n, j]*T1[j, k], {j, 0, n}]; %t A127253 Table[T[n, k], {n, 0, 12}, {k, 0, n}] // Flatten (* _Amiram Eldar_, Aug 04 2023 *) %Y A127253 Row sums are A127254. %Y A127253 Cf. A000069, A091855, A127243, A127248. %K A127253 sign,tabl %O A127253 0,1 %A A127253 _Paul Barry_, Jan 10 2007