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 A257258 #11 Sep 20 2016 13:27:15 %S A257258 1,1,3,1,3,7,1,3,8,12,1,3,7,14,22,1,3,8,13,24,30,1,3,7,14,24,30,42,1, %T A257258 3,8,12,26,32,43,61,1,3,7,13,24,33,47,63,71,1,3,8,14,24,31,43,66,72, %U A257258 88,1,3,7,13,22,30,47,60,73,83,108,1,3,8,12,24,32,43,66,71,90,117,126 %N A257258 Square array A(row,col) = (1/2) * (A255127(row,col+1) - A255127(row,col)): half of the first differences of each row of Ludic array. %C A257258 The array A(row,col) is read by downwards antidiagonals as A(1,1), A(1,2), A(2,1), A(1,3), A(2,2), A(3,1), ... %H A257258 Antti Karttunen, <a href="/A257258/b257258.txt">Table of n, a(n) for n = 1..10440; the first 144 antidiagonals of the array</a> %F A257258 A(row,col) = (1/2) * (A255127(row,col+1) - A255127(row,col)). %F A257258 A(row,col) = A257257(row,col)/2. %e A257258 The top left corner of the array: %e A257258 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 %e A257258 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3 %e A257258 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8 %e A257258 12, 14, 13, 14, 12, 13, 14, 13, 12, 14, 13, 14, 12, 13, 14, 13 %e A257258 22, 24, 24, 26, 24, 24, 22, 24, 26, 24, 24, 24, 22, 26, 24, 24 %e A257258 30, 30, 32, 33, 31, 30, 32, 31, 30, 35, 30, 30, 31, 32, 30, 33 %e A257258 42, 43, 47, 43, 47, 43, 41, 46, 44, 46, 44, 45, 45, 42, 45, 45 %e A257258 61, 63, 66, 60, 66, 63, 65, 63, 60, 66, 64, 63, 65, 64, 63, 65 %e A257258 71, 72, 73, 71, 73, 69, 75, 74, 70, 74, 73, 69, 75, 69, 75, 74 %e A257258 88, 83, 90, 84, 88, 89, 85, 89, 85, 90, 87, 86, 88, 89, 88, 87 %e A257258 108, 117, 113, 121, 114, 113, 120, 109, 117, 123, 110, 115, 117, 113, 117, 118 %e A257258 126, 135, 127, 137, 129, 127, 129, 138, 131, 133, 129, 128, 132, 138, 132, 132 %e A257258 137, 142, 134, 142, 152, 135, 141, 139, 147, 141, 141, 138, 141, 144, 146, 138 %e A257258 154, 158, 157, 158, 160, 158, 156, 154, 162, 168, 158, 151, 158, 157, 161, 157 %e A257258 180, 180, 177, 184, 180, 186, 185, 184, 176, 180, 190, 177, 185, 190, 176, 184 %e A257258 206, 217, 212, 210, 213, 220, 213, 210, 216, 212, 211, 222, 212, 211, 215, 213 %e A257258 ... %o A257258 (Scheme) %o A257258 (define (A257258 n) (A257258bi (A002260 n) (A004736 n))) %o A257258 (define (A257258bi row col) (* (/ 1 2) (- (A255127bi row (+ 1 col)) (A255127bi row col)))) ;; Code for A255127bi given in A255127. %Y A257258 Column 1: A256483. %Y A257258 Cf. A255127, A257257 (same array but with terms multiplied by 2). %K A257258 nonn,tabl %O A257258 1,3 %A A257258 _Antti Karttunen_, Apr 29 2015