Extend New Binary Sequence ?
Paul D. Hanna
pauldhanna at juno.com
Sat Sep 1 01:48:11 CEST 2007
Seqfans,
Could someone also extend the following sequence.
It appears in an interesting tree structure that I am studying.
Definition:
a(n) = A000123( A000975(n-1) ) for n>=1 with a(0)=1,
where A000123(n) = number of partitions of 2n into powers of 2
and A000975(n) = n-th number without consecutive equal binary digits.
The sequence begins:
1,1,2,4,14,60,450,4964,95982,3037948,
but I can get no further before my old PARI gets "deep recursion".
This is an equivalent definition using PARI:
a(n) = if(n==0,1, A000123( (2^(n+2) - (-1)^n - 3)/6 ) )
where
A000123(n) = if(n<1, n==0, A000123(n\2) + A000123(n-1))
Thanks for any help,
Paul
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