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Search: id:A091645
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| A091645 |
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Number of primes less than 10^n having at least one digit 1. |
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+0
3
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| 0, 8, 67, 559, 4917, 44073, 402030, 3709989, 34534791, 323587790, 3046685950, 28798331502
(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) = 8 because of the 25 primes less than 10^2, 8 have at least one 1 digit.
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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], 1] != {}, c++ ]]; Print[c]; p--, {n, 1, 8}] (from Robert G. Wilson v Feb 02 2004)
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], 2] != {}, 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) + A091635(n) = A006880(n).
Cf. A091645, A091646, A091647, A091705, A091706, A091707, A091708, A091709, A091710.
Sequence in context: A166797 A037594 A037685 this_sequence A015574 A152055 A000434
Adjacent sequences: A091642 A091643 A091644 this_sequence A091646 A091647 A091648
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KEYWORD
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more,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, corrected 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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