[seqfan] Re: Trivial array of powers
Richard J. Mathar
mathar at mpia-hd.mpg.de
Wed Dec 9 18:05:51 CET 2015
In http://list.seqfan.eu/pipermail/seqfan/2015-December/015806.html I
was using "alphabet" in the usual sense of combinatorics. Of course,
rejecting only words that have clusters of three or more repeated letters
is no longer a "trivial" array, but more like this:
1 2 3 4 5 6 7 8
1 4 9 16 25 36 49 64
0 6 24 60 120 210 336 504
0 10 66 228 580 1230 2310 3976
0 16 180 864 2800 7200 15876 31360
0 26 492 3276 13520 42150 109116 247352
0 42 1344 12420 65280 246750 749952 1950984
0 68 3672 47088 315200 1444500 5154408 15388352
with 2nd column in A006355, 3rd in A121907, 4th in A123620, 5th in A123871 etc.
Richard Mathar
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