OFFSET
1,2
COMMENTS
Since, e.g., 27=17+2*3+4*1 and 17=a(3),3=a(2),1=a(1), then 27 has "coordinates" (3,2,1). Thus we have a one-to-one map of odd integers >=7 to the positive lattice points in the three-dimensional space.
FORMULA
a(n)=2A033045(n-1)+1
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Nov 15 2008
STATUS
approved