61237domain: NAppears in sequencesTriangular array read by rows: T(n,1) = T(n,n) = 1, T(n,k) = 3*T(n-1,k-1) + 2*T(n-1,k).at n=52A119725Number of integer-sided hexagons having perimeter n.at n=42A124286a(n) is the sum of the digits of all positive integers k <= 2^n.at n=12A319733a(n) = Sum_{d|n} (n/d) * 3^(n-d).at n=8A359203