OFFSET
0,3
COMMENTS
Equals the number of nodes at generation n in the 4-convoluted tree, which is defined as follows: tree of all finite sequences {c(k), k=0..n} that form the initial terms of a self-convolution 4th power of some integer sequence such that 0 < c(n) <= 4*c(n-1) for n>0 with a(0)=1. - Paul D. Hanna, Oct 06 2007
LINKS
EXAMPLE
a(n) counts the nodes in generation n of the following tree.
Generations 0..3 of the 4-convoluted tree are as follows;
The path from the root is shown, with child nodes enclosed in [].
GEN.0: [1];
GEN.1: 1->[4];
GEN.2: 1-4->[2,6,10,14];
GEN.3:
1-4-2->[4,8]
1-4-6->[4,8,12,16,20,24]
1-4-10->[4,8,12,16,20,24,28,32,36,40]
1-4-14->[4,8,12,16,20,24,28,32,36,40,44,48,52,56].
Each path in the tree from the root node forms the initial terms of a self-convolution 4th power of a sequence of integer terms.
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Sep 19 2007, Oct 06 2007
EXTENSIONS
Extended by Martin Fuller, Sep 24 2007
STATUS
approved