CorGenmeasures long-range correlations in DNA sequences and can generate random sequences with the same (or user-specified) correlation and composition parameters.
Quadruplex forming G-Rich Sequences (QGRS) Mapper searches nucleotide sequences for the presence of G-quartet motifs. QGRS Mapper allows you to view the distribution and composition of QGRS in the context of alternatively spliced isoforms of your gene.