Given a row of n payphones (or phone booths), all initially unused, sequence gives number of ways for n people to choose the payphones assuming each always chooses one of the most distant payphones from those in use already.

A095236

Given a row of n payphones (or phone booths), all initially unused, sequence gives number of ways for n people to choose the payphones assuming each always chooses one of the most distant payphones from those in use already.

Terms

    a(0) =1a(1) =2a(2) =4a(3) =8a(4) =16a(5) =36a(6) =136a(7) =216a(8) =672a(9) =2592a(10) =10656a(11) =35904a(12) =167808a(13) =426240a(14) =1866240a(15) =15287040a(16) =35573760a(17) =147640320a(18) =1323970560a(19) =3104317440a(20) =64865525760a(21) =352235520000

External references