OFFSET
1,1
LINKS
EXAMPLE
At stage 1 we place a toothpick anywhere in the plane (for example, in vertical position). There are two exposed endpoints, so a(1)=2.
At stage 2 we place 4 toothpicks: two new toothpicks touching each exposed endpoint. There are now 4 exposed endpoints, so a(2)=4.
CROSSREFS
KEYWORD
nonn
AUTHOR
Olaf Voß, Dec 24 2010
STATUS
approved