Number of n-digit "Punctual Birds" (cf. A131881).

A132133

Number of n-digit "Punctual Birds" (cf. A131881).

Terms

    a(0) =1a(1) =9a(2) =45a(3) =270a(4) =2104a(5) =16941a(6) =142245a(7) =1226146

External references