The gfun package is useful for finding generating functions and linear recurrences satisfied by sequences, given the first few terms. In order for it to work for your first example, you would actually need a couple more terms.
A:= [100, 101, 97, 106, 90, 115, 79, 128, 64, 145, 45]:
Another useful resource is the On-Line Encyclopedia of Integer Sequences, which is a searchable database of over a quarter-million such sequences (more being added every day). This particular one is not there, but your second example is: a search for 0, 1, 8, 11, 69, 88 finds sequence A000787.
Although the OEIS does not have the first sequence, it does have a "super-seeker" that can relate it to sequences that it does have. Email to firstname.lastname@example.org with no subject and a line
lookup 100 101 97 106 90 115 79
will (after a few minutes) get a return email describing many sequences related to this one by various transformations.