cp's OEIS Frontend

A092697 For 1 <= n <= 9, a(n) = least number m such that the product n*m is obtained merely by shifting the rightmost digit of m to the left end (a finite sequence).

%I A092697 #31 Dec 23 2022 07:38:00
%S A092697 1,105263157894736842,1034482758620689655172413793,102564,142857,
%T A092697 1016949152542372881355932203389830508474576271186440677966,
%U A092697 1014492753623188405797,1012658227848,10112359550561797752808988764044943820224719
%N A092697 For 1 <= n <= 9, a(n) = least number m such that the product n*m is obtained merely by shifting the rightmost digit of m to the left end (a finite sequence).
%C A092697 This is the least n-parasitic number. A k-parasitic number (where 1 <= k <= 9) is one such that when it is multiplied by k, the product obtained is merely its rightmost digit transferred in front at the leftmost end.
%D A092697 C. A. Pickover, Wonders of Numbers, Chapter 28, Oxford Univ. Press UK 2000.
%H A092697 Wikipedia, <a href="http://en.wikipedia.org/wiki/Parasitic_number">Parasitic numbers</a> [From Dzmitry Paulenka (pavlenko(AT)tut.by), Aug 09 2009]
%H A092697 P. Yiu, <a href="http://math.fau.edu/yiu/RecreationalMathematics2003.pdf">k-left-transposable integers</a>, Chap.18.2 pp. 168/360 in 'Recreational Mathematics'
%e A092697 102564 is 4-parasitic because we have 102564*4=410256.
%e A092697 For n=5: 142857*5=714285. [Dzmitry Paulenka (pavlenko(AT)tut.by), Aug 09 2009]
%Y A092697 Cf. A094676, A081463.
%Y A092697 For other sequences with the same start, see A128857 and especially the cross-references in A097717.
%K A092697 fini,full,base,nonn
%O A092697 1,2
%A A092697 _Lekraj Beedassy_, Aug 21 2004; corrected Dec 17 2004
%E A092697 Edited by _N. J. A. Sloane_, Apr 13 2009
%E A092697 Corrected to set 5th term to 142857 as this is the least 5-parasitic number. Dzmitry Paulenka (pavlenko(AT)tut.by), Aug 09 2009
%E A092697 a(9) added by _Ian Duff_, Jan 03 2012
%E A092697 Incorrect formula removed by _Alois P. Heinz_, Feb 18 2020