Implementation of algorithms for mining frequent sequences / sequential patterns
[PrefixSpan - Prefix Projected Pattern Growth] (https://www.cs.sfu.ca/~jpei/publications/span.pdf)
[SPAM - Sequential PAttern Mining using A Bitmap Representation] (http://www.philippe-fournier-viger.com/spmf/SPAM.pdf)
[LAPIN-SPAM - LAst Position INduction Sequential PAttern Mining] (http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.105.139&rep=rep1&type=pdf)
[BIDE - BI-Directional Extension pattern closure checking] (http://web.engr.illinois.edu/~hanj/pdf/icde04_bide.pdf)
[De Bruijn sequence] (http://en.wikipedia.org/wiki/De_Bruijn_sequence)
[Bit Twiddling Hacks] (https://graphics.stanford.edu/~seander/bithacks.html)