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%I #14 Mar 02 2021 05:58:39
%S 1,0,3,2,5,8,7,10,13,16,15,18,21,24,27,26,29,32,35,38,41,40,43,46,49,
%T 52,55,58,57,60,63,66,69,72,75,78,77,80,83,86,89,92,95,98,101,100,103,
%U 106,109,112,115,118,121,124,127,126,129,132,135,138,141,144,147,150,153,156
%N Array T(n,k) = (n+k)*(3*n+3*k-5)/2 + (3*k+1), read by ascending antidiagonals.
%C This is an instance of a storing function on N^2 (injective) with density 1/3.
%H John S. Lew and Arnold L. Rosenberg, <a href="https://doi.org/10.1016/0022-314X(78)90035-5">Polynomial indexing of integer lattice-points I. General concepts and quadratic polynomials</a>, Journal of Number Theory, 10(2):215-243, 1978. See Corollary 5.2 p. 211.
%e Array begins:
%e 1 3 8 16 27 ...
%e 0 5 13 24 38 ...
%e 2 10 21 35 52 ...
%e 7 18 32 49 69 ...
%e 15 29 46 66 89 ...
%e ...
%o (PARI) T(n,k) = (n+k)*(3*n+3*k-5)/2 + (3*k+1);
%o matrix(8, 8, n, k, T(n-1, k-1))
%Y Cf. A005449 (first column), A104249 (first row), A140090 (second row), A201279 (diagonal).
%K nonn,tabl
%O 0,3
%A _Michel Marcus_, Mar 01 2021
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