[math-fun] permutations with cycles devoid of sequential elements

take P to be a permutation on the integers, with a cycle representation so that, in any cycle, if k is an element, neither k+1 nor k-1 are. How to count these non-neighbouring P's ? Wouter. =============================== This email is confidential and intended solely for the use of the individual to whom it is addressed. If you are not the intended recipient, be advised that you have received this email in error and that any use, dissemination, forwarding, printing, or copying of this email is strictly prohibited. You are explicitly requested to notify the sender of this email that the intended recipient was not reached.