We obtain exact formulas for moments and generating functions of the height
function of the asymmetric simple exclusion process at one spatial point,
starting from special initial data in which every positive even site is
initially occupied. These complement earlier formulas of E. Lee [J. Stat. Phys.
140 (2010) 635-647] but, unlike those formulas, ours are suitable in principle
for asymptotics. We also explain how our formulas are related to divergent
series formulas for half-flat KPZ of Le Doussal and Calabrese [J. Stat. Mech.
2012 (2012) P06001], which we also recover using the methods of this paper.
These generating functions are given as a series without any apparent Fredholm
determinant or Pfaffian structure. In the long time limit, formal asymptotics
show that the fluctuations are given by the Airy$_{2\to1}$ marginals.Comment: Published at http://dx.doi.org/10.1214/15-AAP1099 in the Annals of
Applied Probability (http://www.imstat.org/aap/) by the Institute of
Mathematical Statistics (http://www.imstat.org