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A202704
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Constructed by the same rule as A185356 and A202690, but with first row 0, 1.
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4
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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, 0, 23, 46, 68, 88, 105, 105, 122, 136, 146, 151, 151, 1141, 1141, 1118, 1072, 1004, 916, 811, 811, 706, 584, 448, 302, 151, 0
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,15
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COMMENTS
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Equals A202690 - A202691.
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LINKS
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Table of n, a(n) for n=1..56.
M. Josuat-Vergès, J.-C. Novelli and J.-Y. Thibon, The algebraic combinatorics of snakes, arXiv preprint arXiv:1110.5272 [math.CO], 2011.
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EXAMPLE
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Triangle begins
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
0 23 46 68 88 105 105 122 136 146 151 151
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PROG
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(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)))); }
tabf(nn) = {for (n=1, nn, for (k=-n, n, if (k, print1(T(n, k), ", ")); ); print; ); } \\ Michel Marcus, Jun 03 2020
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CROSSREFS
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Cf. A007836, A185356, A202690, A202691.
Sequence in context: A290736 A007998 A203899 * A273004 A029931 A350311
Adjacent sequences: A202701 A202702 A202703 * A202705 A202706 A202707
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KEYWORD
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nonn,tabf
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AUTHOR
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N. J. A. Sloane, Dec 23 2011
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EXTENSIONS
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More terms from Michel Marcus, Jun 03 2020
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STATUS
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approved
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