Exploring maximally multipartite entanglement of even n qubits with   N-tangle
  A necessary condition of the maximally multipartite entangled states (MMES) is given via n-tangle. The condition shows that the n-tangle equal zero for the four-, and eight-qubit of MMESs and the n-tangle equal 1 for two- and six- qubits of MMESs. Furthermore,we give the theoretical limitation for maximally ten-qubit and twelve-qubit entangled states. We conjecture that 4n-qubit states of MMES should have n-tangle equal zero and 4n+2-qubit states of MMES should have n-tangle equal one. 
Xin-Wei Zha, Jian-Xia Qi and Yun-Guang Zhang
quant-ph