163186

Appears in sequences

• Given n points in the complex plane, let M(n) the number of distinct Moebius transformations that take 3 distinct points to 3 distinct points. Note that the triples may have some or all of the points in common.at n=8A158121
• a(n) = Sum_{d|n} (-1)^(n/d-1) * binomial(d+3,4).at n=42A366814