

A216216


Square array T, read by antidiagonals: T(n,k) = 0 if nk>=3 or if kn>=3, T(2,0) = T(1,0) = T(0,0) = T(0,1) = T(0,2) = 1, T(n,k) = T(n1,k) + T(n,k1).


11



1, 1, 1, 1, 2, 1, 0, 3, 3, 0, 0, 3, 6, 3, 0, 0, 0, 9, 9, 0, 0, 0, 0, 9, 18, 9, 0, 0, 0, 0, 0, 27, 27, 0, 0, 0, 0, 0, 0, 27, 54, 27, 0, 0, 0, 0, 0, 0, 0, 81, 81, 0, 0, 0, 0, 0, 0, 0, 0, 81, 162, 81, 0, 0, 0, 0
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OFFSET

0,5


LINKS



FORMULA

T(n+1,n) = T(n+2,n) = T(n,n+1) = T(n,n+2) = 3^n = A000244(n).
Sum_{k, 0<=k<=n} T(nk,k) = A068911(n).


EXAMPLE

Square array begins:
1, 1, 1, 0, 0, 0, 0, 0, 0, ... n = 0
1, 2, 3, 3, 0, 0, 0, 0, 0, ... n = 1
1, 3, 6, 9, 9, 0, 0, 0, 0, ... n = 2
0, 3, 9, 18, 27, 27, 0, 0, 0, ... n = 3
0, 0, 9, 27, 54, 81, 81, 0, 0, ... n = 4
0, 0, 0, 27, 81, 162, 243, 243, 0, ... n = 5
....


CROSSREFS



KEYWORD



AUTHOR



STATUS

approved



