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A085977
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Number of 3's in decimal expansion of prime(n).
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10
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0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 2, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 2, 1, 2, 2, 1, 1, 2, 1, 1, 2, 1, 2, 1, 1, 0, 0, 0, 0, 1, 2, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0
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OFFSET
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1,51
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LINKS
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EXAMPLE
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prime(2) = 3, so a(2)=1 and prime(345) = 2333, so a(345)=3.
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MATHEMATICA
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DigitCount[Prime[Range[110]], 10, 3] (* Harvey P. Dale, Aug 05 2019 *)
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PROG
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(Haskell)
a085977 = count3 0 . a000040 where
count3 c x | d == 3 = if x < 10 then c + 1 else count3 (c + 1) x'
| otherwise = if x < 10 then c else count3 c x'
where (x', d) = divMod x 10
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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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