OFFSET
1,1
FORMULA
It seems that a(n) is asymptotic to C*n where C is around 60.
MATHEMATICA
bcdQ[n_]:=Module[{b=Floor[(3/2)^n], b1=Floor[(3/2)^(n+1)], c=Floor[ (4/3)^n], c1=Floor[(4/3)^(n+1)], d=Floor[(5/4)^n], d1=Floor[(5/4)^(n+1)]}, b1/b==3/2&&c1/c==4/3&&d1/d==5/4]; Select[Range[3000], bcdQ] (* Harvey P. Dale, Jun 08 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Apr 06 2003
STATUS
approved