A027094 a(n) = A027082(n, 2n-7).
1, 3, 9, 31, 105, 352, 1168, 3828, 12396, 39698, 125878, 395686, 1234426, 3825911, 11790893, 36160491, 110429221, 336001043, 1019092233, 3082348295, 9300339633, 28002492673, 84156758459, 252507279805, 756547966323
Offset: 4