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 A267089 #15 Jan 12 2016 00:48:50 %S A267089 1,3,3,5,2,5,9,6,6,9,17,10,4,10,17,33,18,12,12,18,33,65,34,20,8,20,34, %T A267089 65,129,66,36,24,24,36,66,129,257,130,68,40,16,40,68,130,257,513,258, %U A267089 132,72,48,48,72,132,258,513,1025,514,260,136,80,32,80,136,260,514 %N A267089 T(n,k) is decimal conversion of 1's in an n X n table that lie on its principal diagonals. %C A267089 Inspired by A137932 and A042948. %C A267089 Conjectures: %C A267089 (i) The first column is A083318. %C A267089 (ii) T(n,k) = A086066(m) where m >= 10, n = m - 9*k, k = floor(m/10). %H A267089 Kival Ngaokrajang, <a href="/A267089/a267089.pdf">Illustration of initial terms</a>, <a href="/A267089/a267089_2.pdf">T(n,k) for n = 0..15, k = 0..10</a> %e A267089 See the "Illustration of initial terms" link for explicit examples. %e A267089 Triangle begins: %e A267089 n\k 0 1 2 3 4 5 6 7 8 ... %e A267089 0 1 %e A267089 1 3 3 %e A267089 2 5 2 5 %e A267089 3 9 6 6 9 %e A267089 4 17 10 4 10 17 %e A267089 5 33 18 12 12 18 33 %e A267089 6 65 34 20 8 20 34 65 %e A267089 7 129 66 36 24 24 36 66 129 %e A267089 8 257 130 68 40 16 40 68 130 257 %e A267089 ... %o A267089 (Small Basic) %o A267089 t[0][0] = 1 %o A267089 t[1][0] = 3 %o A267089 t[1][1] = 3 %o A267089 TextWindow.Write("1, 3, 3, ") %o A267089 For n = 2 To 20 %o A267089 For k = 0 To n %o A267089 If k = 0 Or k = n then %o A267089 t[n][k] = 1 + math.Power(2,n) %o A267089 Else %o A267089 t[n][k] = 2*t[n-2][k-1] %o A267089 EndIf %o A267089 TextWindow.Write(t[n][k]+", ") %o A267089 EndFor %o A267089 Endfor %Y A267089 Cf. A042948, A083318, A086066, A137932. %K A267089 nonn,tabl %O A267089 0,2 %A A267089 _Kival Ngaokrajang_, Jan 10 2016