OFFSET
3,2
FORMULA
G.f.: 16*z^3*(1-z)*(1-z^2)/[1-z+sqrt(1-2*z-3*z^2)]^4.
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
a(27) corrected and more terms from Sean A. Irvine, Sep 24 2019
STATUS
approved