217924025

Appears in sequences

• A threes sequence that gets more even factors out: a(n) = (3^n - 1)*(3^n + 1)/2^(4 - (n mod 2)).at n=10A152299
• a(n) = p(0,n), where p(x,n) is the strong divisibility sequence of polynomials based on sqrt(3) as in A327321.at n=19A329008