OFFSET
0,2
LINKS
FORMULA
a(n)=9a(n-1)+10a(n-2)+101^floor((n-2)/2); a(n)=sum{k=0..floor(n/2), binomial(floor(n/2), k)10^(n-2k) }.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Jul 14 2004
STATUS
approved