OFFSET
0,2
LINKS
Minfeng Wang, C++ program to calculate A197487
MATHEMATICA
(* 2x2 case *) cnt = 0; Do[d = Det[{{a, b}, {c, d}}]; If[d != 0, cnt++], {a, 0, 2}, {b, 0, 2}, {c, 0, 2}, {d, 0, 2}]; cnt (* T. D. Noe, Nov 29 2011 *)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Roger Hui, Nov 29 2011
EXTENSIONS
a(5)-a(6) from Minfeng Wang, May 29 2024
a(0)=1 prepended by Alois P. Heinz, May 29 2024
STATUS
approved