I am trying to prove why a polynomial with coefficients of the sequences of Collatz starting by prime number $n$ to the first appearance of $1$ is an irreducible polynomial (I found composite $n$ where the polynomial is not irreducible), also I tried even the reversed polynomial.
> here is my Pari/GP code
collatz(n)={
local(t=n);local(seq= [n]);
while(t!=1,
if(t%2==0,
seq = concat(seq,t/2); t=t/2,
seq = concat(seq,3*t+1);t=3*t+1;
)
);
return(seq);
}
{forprime(p=2,1000000,
C = collatz(p);
P = Pol(C);
Q = Polrev(C);
if (polisirreducible(P)*polisirreducible(Q)==0 , print(p)
))
}
So I can conjecture the following
Assuming the conjecture of Collatz is True, the polynomial P is irreducible for any prime.