430865domain: NAppears in sequencesNumber of (1+1) X (n+1) arrays of permutations of 0..n*2+1 with each element having directed index change 1,0 0,-1 1,2 or -1,1.at n=46A264584Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n-2) + 3, where a(0) = 1, a(1) = 2, b(0) = 3.at n=23A294535