OFFSET
0,3
COMMENTS
(a(n)) is a strong divisibility sequence.
FORMULA
a(n) = p(n,0), where p(n,x) is polynomial defined in A329432.
MATHEMATICA
f[x_] := 2 x^2 + 1; u[0, x_] := 1;
u[1, x_] := f[x]; u[n_, x_] := f[u[n - 1, x]]
Table [u[n, x] /. x -> 0, {n, 0, 10}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Dec 31 2019
STATUS
approved