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 A091918 #7 Feb 06 2022 06:52:02 %S A091918 1,2,1,4,2,1,8,3,3,1,16,4,6,4,1,32,5,10,10,5,1,64,6,15,20,15,6,1,128, %T A091918 7,21,35,35,21,7,1,256,8,28,56,70,56,28,8,1,512,9,36,84,126,126,84,36, %U A091918 9,1,1024,10,45,120,210,252,210,120,45,10,1,2048,11,55,165,330,462,462,330 %N A091918 Inverse of number triangle A091917. %C A091918 Essentially, Pascal's triangle A007318 with first column of 1's replaced by 2^n Row sums are A000225(n+1). Diagonal sums are A000225(n) + A000045(n). %F A091918 Binomial transform of triangle A103451: (1; 1,1; 1,0,1; 1,0,0,1; ...). - _Gary W. Adamson_, Aug 08 2007 %Y A091918 Cf. A103451. %K A091918 nonn,tabl %O A091918 0,2 %A A091918 _Paul Barry_, Feb 13 2004