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A072354
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a(n)-th Fibonacci number is the smallest Fibonacci number containing n digits.
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12
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1, 7, 12, 17, 21, 26, 31, 36, 40, 45, 50, 55, 60, 64, 69, 74, 79, 84, 88, 93, 98, 103, 107, 112, 117, 122, 127, 131, 136, 141, 146, 151, 155, 160, 165, 170, 174, 179, 184, 189, 194, 198, 203, 208, 213, 217, 222, 227, 232, 237
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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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For n>1, a(n) = floor(n*c) (+3) or (+2) where c=log(10)/log(Phi) and Phi is the golden ratio = (1+sqrt(5))/2. - Benoit Cloitre, Aug 21 2002
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EXAMPLE
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a(3) = 12 as the 12th Fibonacci number is the smallest Fibonacci number with 3 digits.
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MATHEMATICA
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Flatten[Table[Position[IntegerLength[Fibonacci[Range[250]]], n, {1}, 1], {n, 50}]] (* Harvey P. Dale, Dec 22 2015 *)
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PROG
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(PARI) digitsIn(x)=1+log(x)\log(10) {d=0; for(n=1, 100000, x=fibonacci(n); digits = digitsIn(x); if (digits!=d, d = digits; write("b072354.txt", digits, " ", n); ))} \\ Harry J. Smith, Nov 29 2008
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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STATUS
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approved
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