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 A182828 #15 Mar 21 2022 15:34:47 %S A182828 1,3,4,9,12,7,27,36,21,10,81,108,63,30,13,243,324,189,90,39,16,729, %T A182828 972,567,270,117,48,19,2187,2916,1701,810,351,144,57,22,6561,8748, %U A182828 5103,2430,1053,432,171,66,25,19683,26244,15309,7290,3159 %N A182828 Array of the numbers (3*i+1)*3^j, i>=0, j>=0, read by antidiagonals. %F A182828 T(i,j) = (3*i+1)*3^j, i>=0, j>=0. %e A182828 Northwest corner: %e A182828 1....3....9...27... %e A182828 4...12...36..108... %e A182828 7...21...63..189... %e A182828 10..30...90..270... %Y A182828 Cf. A000244 (row 1), A016777 (column 1). %Y A182828 Cf. A054582, A182829, A182830. %Y A182828 Terms in ascending order: A026225. %K A182828 nonn,tabl %O A182828 1,2 %A A182828 _Clark Kimberling_, Dec 06 2010