cp's OEIS Frontend

A202704 Constructed by the same rule as A185356 and A202690, but with first row 0, 1.

%I A202704 #16 Oct 05 2020 17:47:54
%S A202704 0,1,0,0,0,1,1,1,1,1,1,0,0,1,2,3,3,4,5,5,23,23,22,20,17,17,14,10,5,0,
%T A202704 0,23,46,68,88,105,105,122,136,146,151,151,1141,1141,1118,1072,1004,
%U A202704 916,811,811,706,584,448,302,151,0
%N A202704 Constructed by the same rule as A185356 and A202690, but with first row 0, 1.
%C A202704 Equals A202690 - A202691.
%H A202704 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 A202704 Triangle begins
%e A202704                    0 1
%e A202704                0   0 0   1
%e A202704             1  1   1 1   1   0
%e A202704          0  1  2   3 3   4   5   5
%e A202704      23 23 22 20  17 17  14  10  5   0
%e A202704    0 23 46 68 88 105 105 122 136 146 151 151
%o A202704 (PARI) T(n,k) = {if ((k==0), return(0)); if (n==1, if (abs(k)==1, if (k>0, return(1), return (0)))); 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 A202704 tabf(nn) = {for (n=1, nn, for (k=-n, n, if (k, print1(T(n, k), ", "));); print;);} \\ _Michel Marcus_, Jun 03 2020
%Y A202704 Cf. A007836, A185356, A202690, A202691.
%K A202704 nonn,tabf
%O A202704 1,15
%A A202704 _N. J. A. Sloane_, Dec 23 2011
%E A202704 More terms from _Michel Marcus_, Jun 03 2020