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A349422 Replace each decimal digit d of n with the digit that is d steps to the left of d. Interpret the digits of n as a cycle: one step to the left from the first digit is considered to be the last.

%I A349422 #18 Dec 28 2021 04:23:20
%S A349422 0,1,2,3,4,5,6,7,8,9,0,11,22,31,44,51,66,71,88,91,20,22,22,22,24,22,
%T A349422 26,22,28,22,0,13,22,33,44,53,66,73,88,93,40,44,42,44,44,44,46,44,48,
%U A349422 44,0,15,22,35,44,55,66,75,88,95,60,66,62,66,64,66,66,66,68,66,0,17,22,37,44,57,66,77,88,97,80,88,82,88,84,88,86,88,88,88,0,19,22,39,44,59,66,79,88,99,0,100
%N A349422 Replace each decimal digit d of n with the digit that is d steps to the left of d. Interpret the digits of n as a cycle: one step to the left from the first digit is considered to be the last.
%C A349422 First differs from A348179 at a(101).
%H A349422 Sebastian Karlsson, <a href="/A349422/b349422.txt">Table of n, a(n) for n = 0..10000</a>
%e A349422 a(3210) = 2020, because:
%e A349422 Moving 3 steps to the left from 3 gives: 3 -> 0 -> 1 -> 2.
%e A349422 Moving 2 steps to the left from 2 gives: 2 -> 3 -> 0.
%e A349422 Moving 1 step to the left from 1 gives: 1 -> 2.
%e A349422 Moving 0 steps to left from 0 gives: 0.
%o A349422 (Haskell)
%o A349422 import Data.Char (digitToInt)
%o A349422 a n = read [s !! mod (i - digitToInt (s !! i)) l | i <- [0..l-1]] :: Integer
%o A349422     where s = show n; l = length s
%o A349422 (Python)
%o A349422 def a(n):
%o A349422     s, l = str(n), len(str(n))
%o A349422     return int("".join(s[(i - int(s[i])) % l] for i in range(l)))
%o A349422 (PARI) a(n) = { my (d=digits(n)); fromdigits(vector(#d, k, d[1+(k-1-d[k])%#d])) } \\ _Rémy Sigrist_, Nov 17 2021
%Y A349422 Cf. A336668 (fixed points), A348179 (to the right).
%Y A349422 Cf. A139337, A346576, A347323.
%K A349422 nonn,base,look
%O A349422 0,3
%A A349422 _Sebastian Karlsson_, Nov 17 2021