30657

Appears in sequences

• a(n) = T(n,2n-2), T given by A027023.at n=10A027051
• Number of safe primes < 10^n.at n=6A188719
• Number of singular 2 X 2 matrices having all elements in {-n,...,n}.at n=26A209981
• Number of forests of rooted plane binary trees (all nodes have outdegree of 0 or 2) with n total nodes.at n=21A222006
• 60-gonal (hexacontagonal) numbers: a(n) = n(29n - 28).at n=33A249911
• G.f. A(x) satisfies: A(x - 2*x*A(x)) = x - x*A(x).at n=6A291813