129608

Appears in sequences

• Number of equilateral triangles formed by triples of points taken from a hexagonal chunk of side n in the hexagonal lattice.at n=16A008893
• Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 90.at n=7A031768
• a(n) = 2025*n^2 + n.at n=7A156856
• Number of steps to reach 1 in '3x+1' (or Collatz) problem starting with the n-th Mersenne prime.at n=20A181777