OFFSET
1,3
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..200
C. G. Bower, Transforms (2)
Cassandra Durell, Stefan Forcey, Level-1 Phylogenetic Networks and their Balanced Minimum Evolution Polytopes, arXiv:1905.09160 [math.CO], 2019.
FORMULA
Doubles (index 2+) under "BIJ" (reversible, indistinct, labeled) transform.
E.g.f.: series reversion of x*(2 - 3*x)/(2*(1-x)). - Andrew Howroyd, Sep 19 2018
MATHEMATICA
m = 21; egf = InverseSeries[x(2 - 3x)/(2(1-x)) + O[x]^m];
CoefficientList[egf, x]*Range[0, m-1]! // Rest (* Jean-François Alcover, Sep 25 2019 *)
PROG
(PARI) Vec(serlaplace(serreverse(x*(2 - 3*x)/(2*(1-x)) + O(x^20)))) \\ Andrew Howroyd, Sep 19 2018
CROSSREFS
KEYWORD
nonn,eigen
AUTHOR
EXTENSIONS
Terms a(18) and beyond from Andrew Howroyd, Sep 19 2018
STATUS
approved