3,3

Essentially different ways 1,2,3,...n can be placed around a circle so that sums of adjacent numbers are distinct.

Cf. A091217, A006967.

Sequence in context: A071533 A000240 A132103 this_sequence A019016 A063859 A034183

Adjacent sequences: A040015 A040016 A040017 this_sequence A040019 A040020 A040021

hard,nonn

Erich Friedman (erich.friedman(AT)stetson.edu)

One more term from Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 25 2007