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The right-hand half-triangle of A185356 (or A202690).
2

%I #10 Jun 03 2020 03:45:17

%S 1,1,2,3,2,0,11,14,16,16,57,46,32,16,0,361,418,464,496,512,512,2763,

%T 2402,1984,1520,1024,512,0,24611,27374,29776,31760,33280,34304,34816,

%U 34816,250737,226126,198752,168976,137216,103936,69632,34816,0

%N The right-hand half-triangle of A185356 (or A202690).

%H M. Josuat-Vergès, J.-C. Novelli and J.-Y. Thibon, <a href="http://arxiv.org/abs/1110.5272">The algebraic combinatorics of snakes</a>, arXiv preprint arXiv:1110.5272 [math.CO], 2011.

%e Triangle begins:

%e 1

%e 1 2

%e 3 2 0

%e 11 14 16 16

%e 57 46 32 16 0

%e 361 418 464 496 512 512

%e ...

%o (PARI) T(n,k) = {if ((k==0), return(0)); if (n==1, if (abs(k)==1, return(1))); if (n%2, if (k<0, sum(j=k+1, n-1, T(n-1,j)), sum(j=k, n-1, T(n-1,j))), if (k<0, sum(j=-n+1, k, T(n-1,j)), sum(j=-n+1, k-1, T(n-1,j))));}

%o tabl(nn) = {for (n=1, nn, for (k=1, n, if (k, print1(T(n, k), ", "));); print;);} \\ _Michel Marcus_, Jun 03 2020

%Y Cf. A185356, A202690, A202816.

%K nonn,tabl

%O 1,3

%A _N. J. A. Sloane_, Dec 25 2011

%E More terms from _Michel Marcus_, Jun 03 2020