OFFSET
1,1
COMMENTS
Numbers with increasingly larger and larger one-digit centers.
REFERENCES
Discovered by Jason Earls.
FORMULA
O.g.f.: -x*(2*x+7)*(5*x-1)/[(-1+x)^2*(-1+10*x)^2]. - R. J. Mathar, Feb 26 2008
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Michael Joseph Halm, Jul 10 2004
STATUS
approved