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 A238206 #18 Feb 21 2014 22:04:07 %S A238206 0,2,1,3,7,4,5,10,22,13,6,16,31,67,40,8,19,49,94,202,121,9,25,58,148, %T A238206 283,607,364,11,28,76,175,445,850,1822,1093,12,34,85,229,526,1336, %U A238206 2551,5467,3280,14,37,103,256,688,1579,4009,7654,16402,9841,15,43,112,310 %N A238206 Square array T(n,k), n>=0, k>=0, read by antidiagonals, where T(0,k) is A007494(k) and T(n,k) = 3*T(n-1,k) + 1 for n>0. %C A238206 Permutation of nonnegative integers. %F A238206 T(n,k) = T(0,k)*3^n + T(n,0) where T(0,k) = (6*k + 1 -(-1)^k)/4 = A007494(k) and T(n,0) = (3^n - 1)/2 = A003462(n). %e A238206 Square array begins: %e A238206 0, 2, 3, 5, 6, 8, 9, ... %e A238206 1, 7, 10, 16, 19, 25, 28, ... %e A238206 4, 22, 31, 49, 58, 76, 85, ... %e A238206 13, 67, 94, 148, 175, 229, 256, ... %e A238206 40, 202, 283, 445, 523, 688, 769, ... %e A238206 121, 607, 850, 1336, 1579, 2065, 2308, ... %e A238206 364, 1822, 2551, 4009, 4738, 6196, 6925, ... %e A238206 1093, 5467, 7654, 12028, 14215, 18589, 20776, ... %e A238206 3280, 16402, 22963, 36085, 42646, 55768, 62329, ... %e A238206 9841, 49207, 68890, 108256, 127939, 167305, 186988, ... %e A238206 ... %Y A238206 Cf. A003462, A007494, A052909, A060816, A237930, A238055 %K A238206 nonn,tabl %O A238206 0,2 %A A238206 _Philippe Deléham_, Feb 20 2014