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Template:Seal triangle Birch

From Wikiversity
triangle Birch (~A139382)    row sums Aster (A135922)
k
n
0 1 2 3 4 5 6 7 sums
0 1 1
1 0 1 1
2 0 1 1 2
3 0 1 4 1 6
4 0 1 13 11 1 26
5 0 1 40 90 26 1 158
6 0 1 121 670 480 57 1 1330
7 0 1 364 4811 7870 2247 120 1 15414

as side of pyramid Ivy

n: adicity = valency
k: depth

  • T(n,k) = (2^k-1) * T(n-1,k) + T(n-1,k-1)
  • second diagonal: Eulerian numbers A000295   a(n) = 2^n - n - 1   (see also A125128, A130103)
  • column 2: A003462   a(n) = (3^n - 1)/2
  • column 3: A016212   a(n) = (7^(n+2) - 3^(n+3) + 2)/24