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A168541 Numbers consisting of either 2's and 0's or 5's and 0's. 5
2, 5, 20, 50, 200, 202, 220, 500, 505, 550, 2000, 2002, 2020, 2022, 2200, 2202, 2220, 5000, 5005, 5050, 5055, 5500, 5505, 5550, 20000, 20002, 20020, 20022, 20200, 20202, 20220, 20222, 22000, 22002, 22020, 22022, 22200, 22202, 22220, 50000, 50005 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
A subset of the divisors of zero in carryless arithmetic mod 10, e.g., 5 * 44 = 0.
LINKS
David Applegate, Marc LeBrun and N. J. A. Sloane, Carryless Arithmetic (I): The Mod 10 Version.
MATHEMATICA
lst = {2, 5}; k = 1; While[k < 10^5, id = Union@ IntegerDigits@k; len = Length@ id; If[ len == 2 && id == {0, 2} || id == {0, 5}, AppendTo[lst, k]]; k++ ]; lst (* Robert G. Wilson v, Jul 12 2010 *)
Join[{2, 5}, Sort[Flatten[Table[Select[FromDigits/@Tuples[{k, 0}, 6], DigitCount[ #, 10, 0]>0 && DigitCount[#, 10, k]>0&], {k, {2, 5}}]]]] (* Harvey P. Dale, Jul 03 2020 *)
CROSSREFS
Sequence in context: A136901 A136897 A098510 * A124264 A274239 A271858
KEYWORD
nonn,base,easy
AUTHOR
EXTENSIONS
More terms from Robert G. Wilson v, Jul 12 2010
STATUS
approved

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Last modified March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)