OFFSET
2,3
MATHEMATICA
a[n_] := A055512[[n+1]]/(n(n-1));
a /@ Range[2, 18] (* Jean-François Alcover, Jan 02 2020 *)
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Christian G. Bower, Nov 15 2000
EXTENSIONS
a(18) from Jean-François Alcover, Jan 02 2020
STATUS
approved