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A tribonacci triangle in which the top two northeast and southeast diagonals consist of tribonacci numbers.
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%I #7 Mar 30 2012 17:25:04

%S 1,1,1,2,1,2,4,2,2,4,7,4,4,4,7,13,7,8,8,7,13,24,13,14,16,14,13,24,44,

%T 24,26,28,28,26,24,44

%N A tribonacci triangle in which the top two northeast and southeast diagonals consist of tribonacci numbers.

%C Uses a Hosoya-like format except that the latter has the Fibonacci recursion. This triangle uses the tribonacci recursion such that every interior number can be obtained by adding the 3 previous numbers, on its diagonal.

%D Thomas Koshy, <"Fibonacci and Lucas Numbers with Applications">John Wiley and Sons, 2001, Chapter 15, pages 187-195, "Hosoya's Triangle".

%F T(n, j) = T(n-1, j) + T(n-2, j) + T(n-3, j); (every interior number can be obtained by adding the three previous numbers, on its diagonal.)

%e T(7,3) = 14 = (8 + 4 + 2) = T(6,3) + T(5,3) + T(4,3).

%Y Cf. A000073, tribonacci numbers, A058071, Hosoya's triangle.

%K nonn

%O 1,4

%A _Gary W. Adamson_, May 24 2003