50903domain: NAppears in sequencesNumber of stacks, or arrangements of n pennies in contiguous rows, each touching 2 in row below.at n=38A001524Number of n X 4 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 3,4,2,0,1 for x=0,1,2,3,4.at n=10A196859