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A072912
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Number of Fibonacci numbers F(k) <= 10^n which end in 0.
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1
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1, 1, 1, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 13, 13, 13, 14, 14, 14, 15, 15, 15, 16, 16, 16, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 20, 20, 20, 21, 21, 21, 22, 22, 22, 23, 23, 23, 24, 24, 24, 25, 25, 25
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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FORMULA
| a(n) =ceil(n*log(10)/15/log(PHI)) +0 or +1
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EXAMPLE
| a(2)=6 because there are 6 Fibonacci numbers F(k) <= 10^2 which end in 0.
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PROG
| (PARI) a(n)=(sum(i=0, ceil(n*log(10)/log((1+sqrt(5))/2)), if(fibonacci(i)%10+1+sign(fibonacci(i)-10^n), 0, 1))
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CROSSREFS
| Different from A002280.
Cf. A008597.
Sequence in context: A051889 A086707 A194920 * A025786 A085886 A088676
Adjacent sequences: A072909 A072910 A072911 * A072913 A072914 A072915
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KEYWORD
| base,nonn
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AUTHOR
| Shyam Sunder Gupta (guptass(AT)rediffmail.com) and Benoit Cloitre, Aug 15 2002
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