A variant of payphone permutations: given a row of n payphones, a(n) is the number ways for n people to choose the payphones in order, where each person chooses an unoccupied payphone such that the closest occupied payphone is as distant as possible, and a payphone adjacent to a single occupied payphone is preferred over a payphone sandwiched between two occupied payphones.
A363785
A variant of payphone permutations: given a row of n payphones, a(n) is the number ways for n people to choose the payphones in order, where each person chooses an unoccupied payphone such that the closest occupied payphone is as distant as possible, and a payphone adjacent to a single occupied payphone is preferred over a payphone sandwiched between two occupied payphones.
Terms
- a(0) =1a(1) =2a(2) =4a(3) =6a(4) =16a(5) =28a(6) =120a(7) =264a(8) =576a(9) =2784a(10) =11040a(11) =37440a(12) =204672a(13) =679680a(14) =2511360a(15) =15655680a(16) =52945920a(17) =232796160a(18) =2456801280a(19) =11867627520a(20) =97875025920a(21) =576737280000
External references
- oeis: A363785