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A334620
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a(n) is the smallest multiple of n formed by the concatenation 1,2,3,...,k for some k.
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1
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1, 12, 12, 12, 12345, 12, 1234567891011, 123456, 12345678, 12345678910, 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106, 12
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) is the smallest multiple of n appearing in A007908.
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EXAMPLE
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a(3) = 12, because 12 is the smallest multiple of 3 that appears in A007908.
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MAPLE
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f:= proc(n) local x, i;
x:= 0;
for i from 1 do
x:= x*10^(1+ilog10(i))+i;
if x mod n = 0 then return x fi
od
end proc:
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MATHEMATICA
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smn[n_]:=Module[{k=1, c=1}, While[!Divisible[c, n], k++; c= c*10^IntegerLength[ k]+ k]; c]; Array[ smn, 20] (* Harvey P. Dale, Apr 04 2022 *)
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PROG
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(PARI) a(n) = j=""; for(k=1, oo, j=eval(concat(Str(j), k)); if(j%n==0, return(j)))
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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