OFFSET
0,3
COMMENTS
LINKS
Peter Luschny, Strong coprimality.
EXAMPLE
a(11) = 11 - card({3,4,6,7,8,9}) = 5.
MAPLE
MATHEMATICA
a[n_] := Select[Range[n], Not[CoprimeQ[#, n] && !Divisible[n-1, #]] &] // Length; a[1] = 0; Table[a[n], {n, 0, 60}] (* Jean-François Alcover, Jun 28 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, Nov 17 2010
STATUS
approved