Fix maxLastSuccessfulOutboundThreshold typo (#1946)

docs/concepts/dht.md

@@ -82,7 +82,7 @@ To keep the routing tables accurate and up to date, IPFS refreshes the routing t
    1. For each bucket, select a random address in the Kademlia space that could fit in that bucket and do a lookup to find the `K` closest peers to that random address. This will ensure that we will have filled up each bucket with as many peers as will fit.
 1. Also, search for ourselves in the network, just in case the network size and distribution are such that the first 15 buckets do not suffice to learn about the `K` peers closest to us.
 
-Peers can be dropped from the routing table for several reasons, usually because that peer is offline or unreachable. After every refresh, IPFS goes through the routing table and attempt to connect to peers that we have not queried recently. If any peers are not active or online, they are dropped from the routing table. Peers can also be dropped if they have not been useful within the time period during which they are _probabilistically expected_ to have been utilized in a refresh. That value is `Log(1/K) * Log(1 - α/K) * refreshPeriod`, where `α` is the number of peers dialed that can be simultaneously queried. Additionally, IPFS defines _useful_ as responding within 2x when it takes any other peer from our routing table to respond to us. This biases against peers that are slow, overloaded, unreliable, or have bad network connectivity to us.
+Peers can be dropped from the routing table for several reasons, usually because that peer is offline or unreachable. After every refresh, IPFS goes through the routing table and attempt to connect to peers that we have not queried recently. If any peers are not active or online, they are dropped from the routing table. Peers can also be dropped if they have not been useful within the time period during which they are _probabilistically expected_ to have been utilized in a refresh. That value is `Log(1/K) / Log(1 - α/K) * refreshPeriod`, where `α` is the number of peers dialed that can be simultaneously queried. Additionally, IPFS defines _useful_ as responding within 2x when it takes any other peer from our routing table to respond to us. This biases against peers that are slow, overloaded, unreliable, or have bad network connectivity to us.
 
 ## Lookup algorithm