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 A279010 #15 Aug 13 2018 09:08:35 %S A279010 1,1,1,3,0,1,3,3,-1,1,9,0,4,-2,1,9,9,-4,6,-3,1,27,0,13,-10,9,-4,1,27, %T A279010 27,-13,23,-19,13,-5,1,81,0,40,-36,42,-32,18,-6,1,81,81,-40,76,-78,74, %U A279010 -50,24,-7,1,243,0,121,-116,154,-152,124,-74,31,-8,1 %N A279010 Alternating Jacobsthal triangle A_3(n,k) read by rows. %H A279010 Kyu-Hwan Lee, Se-jin Oh, <a href="http://arxiv.org/abs/1601.06685">Catalan triangle numbers and binomial coefficients</a>, arXiv:1601.06685 [math.CO], 2016. %e A279010 Triangle begins: %e A279010 1; %e A279010 1, 1; %e A279010 3, 0, 1; %e A279010 3, 3, -1, 1; %e A279010 9, 0, 4, -2, 1; %e A279010 9, 9, -4, 6, -3, 1; %e A279010 27, 0, 13, -10, 9, -4, 1; %e A279010 27, 27, -13, 23, -19, 13, -5, 1; %e A279010 81, 0, 40, -36, 42, -32, 18, -6, 1; %e A279010 81, 81, -40, 76, -78, 74, -50, 24, -7, 1; %e A279010 243, 0, 121, -116, 154, -152, 124, -74, 31, -8, 1; %e A279010 ... %t A279010 A[n_, 0] := 3^Floor[n/2]; %t A279010 A[n_, k_] /; (k<0 || t>n) = 0; %t A279010 A[n_, n_] = 1; %t A279010 A[n_, k_] := A[n, k] = A[n-1, k-1] - A[n-1, k]; %t A279010 Table[A[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* _Jean-François Alcover_, Aug 12 2018 *) %Y A279010 If initial column is omitted, this is very like the Riordan matrix A191582. %Y A279010 Cf. A112468, A279006, A279009. %K A279010 sign,tabl %O A279010 0,4 %A A279010 _N. J. A. Sloane_, Dec 07 2016