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Search: id:A091647
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| A091647 |
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Number of primes less than 10^n having at least one digit 3. |
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+0
4
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| 1, 9, 66, 561, 4877, 43685, 399564, 3694303, 34433999, 322852288, 3041362298, 28758431735
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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a(2) = 9 because of the 25 primes less than 10^2, 9 have at least one digit 3.
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MATHEMATICA
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NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; c = 0; p = 1; Do[ While[ p = NextPrim[p]; p < 10^n, If[ Position[ IntegerDigits[p], 3] != {}, c++ ]]; Print[c]; p--, {n, 1, 8}] (from Robert G. Wilson v Feb 02 2004)
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CROSSREFS
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a(n) + A091637(n) = A006880(n).
Cf. A091637, A091744, A091745, A091746, A091705, A091706, A091707, A091708, A091709, A091710.
Sequence in context: A048439 A134432 A098107 this_sequence A106132 A105287 A163349
Adjacent sequences: A091644 A091645 A091646 this_sequence A091648 A091649 A091650
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KEYWORD
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nonn,base
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AUTHOR
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Enoch Haga (Enokh(AT)comcast.net), Jan 30 2004
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 02 2004
3 more terms from Ryan Propper (rpropper(AT)stanford.edu), Aug 20 2005
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