[seqfan] a(n) shows one of the digits of a(n-1)-1
Eric Angelini
Eric.Angelini at kntv.be
Sun Nov 2 00:55:26 CET 2014
Hello SeqFans,
Start T with a(1)=1
Now a(n) is the smallest integer > 0
not yet in T such that a(n) shows at
least one of the digits of a(n-1)-1.
T=1,10,9,8,7,6,5,4,3,2,11,12,13,14,15,16,17,18,19,21,20,29,22,23,24,25,26,27,28,32,...
I guess T is a permutation of the non-
negative integers.
Why is 32 following 28 (at the end of
the above sequence)?
Because 28 produces the digits 2 and 7
(as 28-1=27) and the smallest available
integer not yet in T showing a 2 or a 7
is precisely 32.
This 32 will produce the digits 3 and 1
(as 32-1=31); the smallest integer
not yet present in T that "includes" a
3 or a 1 is 30. This 30 will thus extend T.
Etc.
Best,
É.
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