OFFSET
1,7
COMMENTS
Series reversion of the g.f. gives the same sequence with two initial terms (1, 1) dropped.
FORMULA
G.f. satisfies A((A(x) - x - x^2)/x^2) = x.
MATHEMATICA
Nest[InverseSeries[#] x^2 + x^2 + x &, x + O[x]^2, 14][[3]]
CROSSREFS
KEYWORD
sign
AUTHOR
Vladimir Reshetnikov, Aug 07 2019
STATUS
approved