OFFSET
0,2
LINKS
FORMULA
G.f.: (1+3*x) / (1-x+16*x^2).
a(n) = Sum_{k=0..n} A133607(n,k)*4^k. - Philippe Deléham, Dec 29 2007
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Philippe Deléham, Dec 28 2007, corrected Jan 04 2008
EXTENSIONS
a(19) corrected and more terms from Sean A. Irvine, May 19 2019
STATUS
approved