[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.


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.


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