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a(n) = least number m such that the quotient m/n is obtained merely by shifting the leftmost digit of m to the right end and the second digit of m is not zero.
7

%I #28 Oct 24 2022 00:06:00

%S 1,210526315789473684,3103448275862068965517241379,410256,714285,

%T 6101694915254237288135593220338983050847457627118644067796,

%U 7101449275362318840579,8101265822784,91011235955056179775280898876404494382022471

%N a(n) = least number m such that the quotient m/n is obtained merely by shifting the leftmost digit of m to the right end and the second digit of m is not zero.

%C Here when the leftmost digit of m is shifted to the right end the number of digits may not decrease - compare A097717.

%C Least n-transposable number. A k-transposable number, 1 <= k <= 9, is one which is k times the number obtained when the leftmost digit is moved to the end.

%D H. Camous, Jouer Avec Les Maths, "Chassez le naturel", Section I, Problem 3 pp. 20; 31-2, Les Editions D'Organisation, Paris 1984.

%D L. A. Graham, Ingenious Mathematical Problems and Methods, "End At The Beginning", Problem 72 pp. 44; 212-3, Dover NY 1959.

%F a(n) = n prepended to n*(10^m - n)/(10*n - 1), where m = A094224(n) - 1.

%e a(4) = 410256 = 4*102564.

%Y Cf. A097717. A249596-A249599.

%K nonn,base,fini,full

%O 1,2

%A _Lekraj Beedassy_, Jun 07 2004

%E Edited by _N. J. A. Sloane_, Apr 13 2009

%E a(5) corrected by _Emilio Martín_, Jul 28 2022