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 A122098 Smallest number, different from 1, which when multiplied by "n" produces a number with "n" as its rightmost digits. 1
 11, 6, 11, 6, 3, 6, 11, 6, 11, 11, 101, 26, 101, 51, 21, 26, 101, 51, 101, 6, 101, 51, 101, 26, 5, 51, 101, 26, 101, 11, 101, 26, 101, 51, 21, 26, 101, 51, 101, 6, 101, 51, 101, 26, 21, 51, 101, 26, 101, 3, 101, 26, 101, 51, 21, 26, 101, 51, 101, 6, 101, 51, 101, 26, 21 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All prime numbers p > 5 must be multiplied by 1+10^k, where k is the number of digits of p. The result is p U p. - Paolo P. Lava, Apr 11 2008 REFERENCES G. Balzarotti and P. P. Lava, Le sequenze di numeri interi, Hoepli, 2008, p. 100 LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 EXAMPLE a(8)=6 because 8*6 = 48 and 6 is the minimum number that multiplied by 8 gives a number ending in 8. a(12)=26 because 12*26=312 and 26 is the minimum number that multiplied by 12 gives a number ending in 12. MAPLE P:=proc(n) local a, b, i, j; print(11); for i from 2 by 1 to n do b:=trunc(evalf(log10(i)))+1; for j from 2 by 1 to n do a:=i*j; if i=a-trunc(a/10^b)*10^b then print(j); break; fi; od; od; end: P(101); # Paolo P. Lava, Apr 11 2008 MATHEMATICA snrd[n_]:=Module[{k=2}, While[Mod[k*n, 10^IntegerLength[n]]!=n, k++]; k]; Array[ snrd, 70] (* Harvey P. Dale, Apr 08 2019 *) CROSSREFS Sequence in context: A236175 A193813 A080501 * A115943 A122088 A304053 Adjacent sequences:  A122095 A122096 A122097 * A122099 A122100 A122101 KEYWORD nonn,base AUTHOR Paolo P. Lava and Giorgio Balzarotti, Oct 18 2006 STATUS approved

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Last modified February 20 12:34 EST 2020. Contains 332076 sequences. (Running on oeis4.)