Given an alphabet of 3 letters i.e. a,b,c evaluate
the number of n-letter words containing even number
of “a”s.
(In reply to
How to get to a closed form? by Larry)
What I would do to find a closed form, assuming I don't want to go through the analytic process, would be to enter the first few numbers in the sequence.
Putting
2,5,14,41,122,365
into the OEIS leads to A007051 as the first of four sequences, except I wasn't including zero a's, so I had
1,6,25,90,301,966
which leads to A000392, Stirling numbers of the second kind.
|
Posted by Charlie
on 2022-04-27 13:39:00 |