17716740096domain: NAppears in sequencesa(n) = n*2^(n-4).at n=29A079859a(0) = a(1) = 1; for n > 1, a(n) = (n+2)*2^(n-2).at n=31A087447Encoded symmetrical antidiagonal square binary matrices with either 1 or 2 ones.at n=18A261819(1/8) times the sum of the elements of all subsets of [n] whose sum is divisible by eight.at n=32A309300