OFFSET
0,6
COMMENTS
MATHEMATICA
terms = 38; gf[-1] = 1; gf[n_] := gf[n] = (1-Sqrt[1-4z^2 gf[n -1]])/(2z);
row[n_] := row[n] = gf[n]/z^n + O[z]^terms // CoefficientList[#, z]&;
row[n = 1]; row[n++]; While[Print[n]; row[n] != row[n-1], n++];
A321397 = row[n] (* Jean-François Alcover, Dec 08 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, Nov 11 2018
STATUS
approved