70598995513domain: NAppears in sequencesBinomial transform of 0, 1, 1, 7, 7, 31, 31, ..., zero followed by duplicated A083420.at n=23A140420a(n) = (1/4)*(9^n - 2*4^n + 3), n > 0; a(0) = 0.at n=12A386359