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A072509
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Number of Fibonacci numbers F(k) <= 10^n which end in 1.
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2
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2, 2, 3, 3, 4, 5, 6, 6, 6, 7, 7, 7, 8, 10, 11, 11, 11, 13, 13, 14, 14, 15, 15, 15, 15, 17, 18, 19, 19, 20, 21, 22, 22, 22, 23, 23, 23, 23, 26, 27, 27, 27, 29, 29, 30, 30, 31, 31, 31, 31, 32, 34, 35, 35, 36, 37, 38, 38, 38, 39, 39, 39, 39, 42, 42, 43, 43, 45, 45, 46, 46, 47, 47
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OFFSET
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0,1
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COMMENTS
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Note that F(k) ends in 1 if and only if k == 1, 2, 8, 19, 22, 28, 41, or 59 (mod 60). - Robert Israel, May 14 2018
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LINKS
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MAPLE
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N:= 100: m:= 0:
A:= Array(0..N):
A[0]:= 2:
for i from 0 while m <= N do
for j in [1, 2, 8, 19, 22, 28, 41, 59] do
m:= ilog10(combinat:-fibonacci(60*i+j))+1;
if m > N then break fi;
A[m..N]:= A[m..N]+1;
od od:
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MATHEMATICA
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With[{s = Array[Fibonacci, 350]}, Table[Count[TakeWhile[s, # <= 10^n &], _?(Mod[#, 10] == 1 &)], {n, 0, IntegerLength@ Max@ s}] ] (* Michael De Vlieger, May 14 2018 *)
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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STATUS
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approved
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