T(n,k)=Number of city-block distance 1, pressure limit 2 movements in an nXk array with each element moving exactly one horizontally or vertically and no element acquiring more than two neighbors.

A217028

T(n,k)=Number of city-block distance 1, pressure limit 2 movements in an nXk array with each element moving exactly one horizontally or vertically and no element acquiring more than two neighbors.