OFFSET
0,2
COMMENTS
A087457 gives number of odd length roads between any adjacent nodes in virtual optimal chordal ring of degree 3.
EXAMPLE
Given a(1)=1 and a(1)=2, then a(2)=4 since sum of first 3 coefficients of
A(x)^3=1+6x+24x^2+... equals 1+6+24 = 31 = A087457(3).
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Oct 24 2003
STATUS
approved