2,1

a(6) (shown) = 1386*2196^21, a(7) (too large to show) = 16814*37004^27.

Table of n, a(n) for n=2..6.

Elmar Teufl and Stephan Wagner, Exact and asymptotic enumeration of perfect matchings in self-similar graphs, Discrete Mathematics 309(23-24) (2009), 6612-6625; see Table 1 (p. 6619).

Cf. A324125.

Sequence in context: A201959 A216187 A178446 * A272662 A125812 A093657

Adjacent sequences: A324123 A324124 A324125 * A324127 A324128 A324129

nonn

N. J. A. Sloane, Feb 16 2019

approved