[seqfan] New old idea: the last digit of a(n) is a copy of the a(n+1)st digit of the sequence itself

Eric Angelini Eric.Angelini at kntv.be
Mon Sep 29 15:54:07 CEST 2014


The same idea, even smoother than the
previous one to compute (at least by hand):

V=1,3,10,4,5,6,7,8,30,11,12,2,15,18,9,21,13,25,27,80,31,14,35,37,29,41,17,39,47,45,51,19,55,52,16,61,23,32,22,26,62,28,20,77,49,81,24,42 40,89,91,33,36,71,34,48,75,56,72,59,...

Lexico-first permutation of the integers > 0 such that the last digit
of a(n) is a copy of the a(n+1)st digit of V, the sequence itself.

Example:
-the 10th digit of V is 3 (because 3 is the digit preceding immediately 10)
 (indeed, it is the 3 in 30)
-the 4th digit of V is 0 (because 0 is the digit preceding immediately 4)
 (indeed, it is the 0 of 10)
-the 59th digit of V (look at the present end of V) is 2 (because 2 is 
 the digit preceding immediately 59 -- indeed, it is the 2 of 52) etc.
Best,
É.



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