OFFSET
0,3
COMMENTS
The sequence gives the number of pentagons in the structure after n-th stage. A222173 (the first differences) gives the number of pentagons added at n-th stage.
Also P-toothpick sequence starting near of the vertex of an infinite 36-degree wedge, since each pentagon can be replaced by a P-toothpick.
For more information see A222180.
First differs from A153000 at a(9).
LINKS
FORMULA
a(n) = (A222180(n+2) - 6)/10. - Omar E. Pol, Nov 24 2013
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Omar E. Pol, Mar 21 2013
EXTENSIONS
Name improved by Omar E. Pol, Nov 24 2013
STATUS
approved