321776

Appears in sequences

• The number of Apollonian networks (planar 3-trees) with n+3 vertices.at n=11A027610
• a(n) = (prime(n)^6 - prime(n)^2)/15.at n=5A138448
• G.f.: A(x) = Sum_{n>=0} log(1+x + 2^n*x^2)^n/n!.at n=10A159322
• Number of n X 3 1..3 arrays containing at least one of each value, all equal values connected, rows considered as a single number in nondecreasing order, and columns considered as a single number in decreasing order.at n=15A166842