[seqfan] Self-describing chunks -- more magic!

[Eric Angelini]

Hello SeqFans,
This is, I guess, the upper level of self-description:

U=1,2,4,3,5,6,7,23,29,37,20,53,73,31,
22,223,59,227,233,71,25,257,277,337,
353,373,523,27,79,557,577,727,733,
757,773,33,2237,2273,263,2333,2357,
2377,2557,2753,2777,3253,3257,3323,
13,3373,3527,3533,3557,2221,3727,
3733,5227,5233,5237,35,5273,5323,
5333,5527,5557,5573,5737,2239,...

As before, mark every non-prime (and
hit "carriage return"):

U=
(1),2,
(4),3,5,
(6),7,23,29,37,
(20),53,73,31,
(22),223,59,227,233,71,(25),257,277,337,353,373,523,(27),79,557,577,727,733,757,773,(33),2237,2273,263,2333,2357,
2377,2557,2753,2777,3253,3257,3323,13,3373,3527,3533,3557,2221,3727,3733,5227,5233,5237,
(35),5273,5323,5333,5527,5557,5573,5737,2239,...

And now, as before, the chunks of non-marked integers have each their 
size given by U itself: 1,2,4,3,5,6,7,23,...

The funny part: if you mark the non-prime
_digits_ of U (instead of the _non-primes_ of U), 
you will see that the "chunk-size-
game" result will be the same -- see:

U=(1),2,(4),3,5,(6),7,23,2(9),37,2(0),
53,73,3(1),22,223,5(9),227,233,7(1),
25,257,277,337,353,373,523,27,7(9),
557,577,727,733,757,773,33,2237,
2273,2(6)3,2333,2357,2377,2557,
2753,2777,3253,3257,3323,(1)3,3373,
3527,3533,3557,222(1),3727,3733,
5227,5233,5237,35,5273,5323,5333,
5527,5557,5573,5737,223(9),...

The _digit-chunks_ of U have their sizes
dictated by U itself: 1,2,4,3,5,6,7,23,29,37,20,53,...
(for instance at the end of the example
immediately above, there are 53
_non-prime digits_ between the (1) of
222(1) and the (9) of 223(9).

This was done by hand and aspirine,
-- please forgive the typos.
[And I'm pretty sure U is another permutation of the integers >0.]

Best,
É.