428064

Appears in sequences

• Number of geometrically distinct open knight's tours of a 3 X n chessboard that have twofold symmetry.at n=21A169776
• a(n) is the number of convex pentagons in an n-triangular net.at n=25A176646
• Sequence lists numbers k > 1 such that k^2 == phi(k) (mod sigma(k)), where phi = A000010 and sigma = A000203.at n=34A324214