OFFSET
1,2
COMMENTS
The sequence excludes the null polyomino of size 0. - John Mason, Jan 10 2023
LINKS
John Mason, Table of n, a(n) for n = 1..50
FORMULA
a(n) = Sum_{k=1..n} A000105(k). - John Mason, Jan 10 2023
a(n) = A173271(n) - 1. - John Mason, Feb 21 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Tanya Khovanova, Jul 23 2007
EXTENSIONS
Offset corrected by John Mason, Jan 10 2023
STATUS
approved