OFFSET
0,2
FORMULA
Row sums of triangle A166880, which lists the coefficients in the iterations of x+x^2+x^3.
MATHEMATICA
NestList[#+#^2+#^3&, 1, 5] (* Harvey P. Dale, Sep 22 2024 *)
PROG
(PARI) a(n)=if(n==0, 1, a(n-1)+a(n-1)^2+a(n-1)^3)
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Nov 21 2009
STATUS
approved