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 A153279 #3 Mar 30 2012 17:25:33 %S A153279 1,2,1,4,2,3,8,4,6,9,16,8,12,18,27,32,16,24,36,54,81,64,32,48,72,108, %T A153279 162,243,128,64,96,144,216,324,486,729,256,128,192,288,432,648,972, %U A153279 1458,2187,512,256,384,576,864,1296,1944,2916,4374,6561 %N A153279 Eigentriangle by rows, T(n,k) = A000079(n-k) * (diagonalized matrix of (1,1,3,9,27,81,...)). %C A153279 Row sums = 3^n %C A153279 Sum of n-th row terms = rightmost term of next row. %C A153279 Eigensequence of the triangle = A153280: (1, 3, 15, 165, 4785, 397155,...) %F A153279 Triangle read by rows, M*Q. M = triangle T(n,k) = A000079(n-k); powers of 2 in every column. Q = an infinite lower triangular matrix with powers of 3 prefaced with a 1: (1,1,3,9,27,...) as the main diagonal and the rest zeros. %e A153279 First few rows of the triangle = %e A153279 1; %e A153279 2, 1; %e A153279 4, 2, 3; %e A153279 8, 4, 6, 9; %e A153279 16, 8, 12, 18, 27; %e A153279 32, 16, 24, 36, 54, 81; %e A153279 64, 32, 48, 72, 108, 162, 243; %e A153279 128, 64, 96, 144, 216, 324, 486, 729; %e A153279 256, 128, 192, 288, 432, 648, 972, 1458, 2187; %e A153279 512, 256, 384, 576, 864, 1296, 1944, 2916, 4374, 6561; %e A153279 ... %e A153279 Row 3 = (8, 4, 6, 9) = termwise products of (8, 4, 2, 1) and (1, 1, 3, 9). %Y A153279 Cf. A000079, A000244, A153280 %K A153279 nonn,tabl %O A153279 0,2 %A A153279 _Gary W. Adamson_, Dec 23 2008