450296

Appears in sequences

• Total number of even lists in all sets of lists, cf. A000262.at n=8A102290
• Denominators a(n) of Pythagorean approximations b(n)/a(n) to Pi.at n=7A195544
• Irregular triangular array read by rows T(n,k) is the number of 2-colored labeled graphs that have exactly k edges, n >= 2, 0 <= k <= A033638(n).at n=50A201143