OFFSET
1,3
LINKS
Jonathan Chappelon, Periodic balanced binary triangles, arXiv:1702.03236 [math.CO], 2016. See Table 1.
MATHEMATICA
a[n_] := Table[Mod[Binomial[n, Abs[i-j]], 2], {i, n}, {j, n}] // NullSpace // Length;
Array[a, 100] (* Jean-François Alcover, Sep 28 2018 *)
PROG
(PARI) a(n) = matsize(matker(matrix(n, n, i, j, binomial(n, abs(i-j)) % 2)))[2];
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Feb 18 2017
STATUS
approved