533619domain: NAppears in sequencesa(n) = Sum_{k <= n/2} binomial(n-2k, 3k+2).at n=26A137358Number of (n+1) X (1+1) arrays of permutations of 0..n*2+1 with each element having directed index change -2,0 -1,0 0,-1 or 1,1.at n=39A264622Expansion of 1/(1 - x^3/(1-x)^5).at n=17A369804