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Array read by antidiagonals: T(m,n) = number of (undirected) paths in the grid graph P_m X P_n.
12

%I #9 Dec 02 2022 13:28:37

%S 0,1,1,3,12,3,6,49,49,6,10,146,322,146,10,15,373,1618,1618,373,15,21,

%T 872,7119,14248,7119,872,21,28,1929,28917,111030,111030,28917,1929,28,

%U 36,4118,111360,801756,1530196,801756,111360,4118,36

%N Array read by antidiagonals: T(m,n) = number of (undirected) paths in the grid graph P_m X P_n.

%C Paths of length zero are not counted here.

%H Andrew Howroyd, <a href="/A288518/b288518.txt">Table of n, a(n) for n = 1..276</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/GraphPath.html">Graph Path</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/GridGraph.html">Grid Graph</a>

%e Table starts:

%e =================================================================

%e m\n| 1 2 3 4 5 6 7

%e ---|-------------------------------------------------------------

%e 1 | 0 1 3 6 10 15 21 ...

%e 2 | 1 12 49 146 373 872 1929 ...

%e 3 | 3 49 322 1618 7119 28917 111360 ...

%e 4 | 6 146 1618 14248 111030 801756 5493524 ...

%e 5 | 10 373 7119 111030 1530196 19506257 235936139 ...

%e 6 | 15 872 28917 801756 19506257 436619868 9260866349 ...

%e 7 | 21 1929 111360 5493524 235936139 9260866349 343715004510 ...

%e ...

%Y Rows 2-7 are A288516, A288527, A358800, A358801, A358802, A358803.

%Y Main diagonal is A288032.

%Y Cf. A231829, A064298, A271465, A271592, A120443, A001184, A145157, A003763.

%K nonn,tabl

%O 1,4

%A _Andrew Howroyd_, Jun 10 2017