STATUS
reviewed
approved
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Revision History for A122098
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Smallest number, different from 1, which when multiplied by "n" produces a number with "n" as its rightmost digits.
(history; published version)
(history; published version)
STATUS
proposed
reviewed
STATUS
editing
proposed
REFERENCES
G. Giorgio Balzarotti and P. Paolo P. Lava, Le sequenze di numeri interi, Hoepli, 2008, p. 100.
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.
CROSSREFS
Cf. A080501.
PROG
(Python)
def a(n):
kn, s = 2*n, str(n)
while not str(kn).endswith(s): kn += n
return kn//n
print([a(n) for n in range(1, 66)]) # Michael S. Branicky, Nov 06 2021
STATUS
approved
editing
STATUS
editing
approved
LINKS
Harvey P. Dale, <a href="/A122098/b122098.txt">Table of n, a(n) for n = 1..1000</a>
STATUS
approved
editing
STATUS
editing
approved
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 *)
STATUS
approved
editing
STATUS
editing
approved