G.f.: Sum_{n>=0} (1 + (1+x)^n)^n / 3^(n+1).

A301307

G.f.: Sum_{n>=0} (1 + (1+x)^n)^n / 3^(n+1).

Terms

    a(0) =1a(1) =5a(2) =98a(3) =3239a(4) =150176a(5) =8958473a(6) =653364947a(7) =56325265925

External references