The mPW2PLYP-D, B2PLYP-D and M0N-2X functionals are applied to predict structures and energies of (C2H6)(n) with n <= 8. A comparison between DFT, DFT-D and CCSD(T) results shows that DFT-D delivers accurate binding energies, while M06-2X performs at a reduced cost relative to DFT-D. Incremental M06-2X clustering free energies for (C2H6) n reveal magic number effects for n = 6-7, and these become increasingly more exergonic as the temperature shifts below 70 K. Results from M06-2X calculations give an accurate and computationally affordable description of interactions between C2H6 molecules, and can be applied to predict the stability and abundance of ethane cluster in Titan's atmosphere. (C) 2014 Elsevier B.V. All rights reserved.