clustering coefficient

[source,cypher]
----
create (_16:`Person` {`name`:"c0"})
create (_17:`Person`)
create (_18:`Person`)
create (_19:`Person`)
create (_20:`Person` {`name`:"c1"})
create (_21:`Person`)
create (_22:`Person`)
create (_23:`Person`)
create (_24:`Person` {`name`:"c2"})
create (_25:`Person`)
create (_26:`Person`)
create (_27:`Person`)
create (_28:`Person` {`name`:"c3"})
create (_29:`Person`)
create (_30:`Person`)
create (_31:`Person`)
create _16-[:`KNOWS`]->_19
create _16-[:`KNOWS`]->_17
create _16-[:`KNOWS`]->_18
create _20-[:`KNOWS`]->_22
create _20-[:`KNOWS`]->_23
create _20-[:`KNOWS`]->_21
create _21-[:`KNOWS`]->_22
create _24-[:`KNOWS`]->_26
create _24-[:`KNOWS`]->_27
create _24-[:`KNOWS`]->_25
create _25-[:`KNOWS`]->_26
create _25-[:`KNOWS`]->_27
create _28-[:`KNOWS`]->_29
create _28-[:`KNOWS`]->_30
create _28-[:`KNOWS`]->_31
create _29-[:`KNOWS`]->_30
create _29-[:`KNOWS`]->_31
create _30-[:`KNOWS`]->_31
----

Query returning wrong results (comparing with https://en.wikipedia.org/wiki/Clustering_coefficient#Local_clustering_coefficient)

[source,cypher]
----
MATCH (a)-[:KNOWS]-()-[r:KNOWS]-()-[:KNOWS]-(a)
WHERE exists(a.name)
WITH a, count(distinct r) AS connected_neighbours
WHERE connected_neighbours>1
RETURN a.name, toFloat(connected_neighbours)/(connected_neighbours*(connected_neighbours-1))
----