[seqfan] Look and Say novelty?
Eric Angelini
Eric.Angelini at kntv.be
Wed Jan 28 19:25:08 CET 2009
Hello SeqFans,
I like this finite one -- which kind of self-constructs nicely:
S = 1, 213223, 31424344,
4152535455,
516263646566,
61727374757677,
7182838485868788,
819293949596979899.
... a(n) says: "Look, we have so far in the sequence (including my
digits), this quantity of digits 'a', that quantity of digits 'b',
etc."
Example: a(2) says "there are two 1's so far (including my digits)"
-> yes, the '1' of a(1) and the '1' of a(2);
"there are three 2's so far"
-> yes, my three 2's;
"there are two 3's so far"
-> yes, my two 3's.
a(3) says "there are three 1's, four 2's, four 3's, four 4's
so far (including my digits)"
-> yes, ...
Are there other such sequences, with different start for instance?
And if this sequence is submitted, does a(2) have to be written 212332?
Best,
É.
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