  A sequence search method was developed for searching for regular frequency
spacing in delta Scuti stars by visual inspection and algorithmic search. The
sample contains 90 delta Scuti stars observed by CoRoT. An example is given to
represent the visual inspection. The algorithm (SSA) is described in detail.
The data treatment of the CoRoT light curves, the criteria for frequency
filtering and the spacings derived by two methods (three approaches: VI, SSA
and FT) are given for each target. Echelle diagrams are presented for 77
targets, for which at least one sequence of regular spacing was identified.
Comparing the spacing and the shifts between pairs of echelle ridges revealed
that at least one pair of echelle ridges is shifted to midway between the
spacing for 22 stars. The estimated rotational frequencies compared to the
shifts revealed rotationally split doublets, triplets and multiplets not only
for single frequencies, but for the complete echelle ridges in 31 delta Scuti
stars. Using several possible assumptions for the origin of the spacings, we
derived the large separation ($\Delta\nu$), which are distributed along the
mean density versus large separations relation derived from stellar models
Suarez 2014.
