See Table 1 on page 3605 of Balaban and Schleyer paper.
A. T. Balaban and Paul von R. Schleyer, "Graph theoretical enumeration of polymantanes", Tetrahedron, (1978), vol. 34, pp. 3599 - 3609..
Table of n, a(n) for n=1..7.
If n=5 then the total numbers of C-rotamers is 7 which is the fifth term in the sequence.
Sequence in context: A287892 A002870 A096579 * A176829 A133206 A054092
Adjacent sequences: A120537 A120538 A120539 * A120541 A120542 A120543
Parthasarathy Nambi, Aug 16 2006