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.
a:= n-> coeff (series (sqrt (add (exp (x*(2^k-2)) *x^k/k!, k=0..n)), x, n+1), x, n)*n!: seq (a(n), n=0..20); # Alois P. Heinz, Sep 12 2008
1, 1, 1, 3, 3, 1, 19, 15, 6, 1, 195, 125, 45, 10, 1, 3031, 1545, 480, 105, 15, 1,
nn=9;f[x_]:=Sum[Sum[Binomial[n,k]2^(k(n-k)),{k,0,n}]x^n/n!,{n,0,nn}];Map[Select[#,#>0&]&,Drop[Range[0,nn]!CoefficientList[Series[Exp[y Log[f[x]]/2],{x,0,nn}],{x,y}],1]]//Grid
# uses[bell_matrix from A264428, A001832] # Adds 1,0,0,0,... as column 0 to the triangle. bell_matrix(lambda n: A001832(n+1), 8) # Peter Luschny, Jan 21 2016
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