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Search: id:A091706
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| A091706 |
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Number of primes less than 10^n having at least one digit 5. |
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+0
8
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| 1, 3, 32, 324, 3282, 31949, 309669, 2995706, 28891689, 278270868, 2678674624, 25780340194
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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a(1) = 1 because of the 4 primes less than 10^1, 1 has at least one digit 5.
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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], 5] != {}, 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) + A091639(n) = A006880(n).
Cf. A091744, A091745, A091746, A091747, A046029, A091707, A091708, A091709, A091710.
Sequence in context: A037792 A037673 A037799 this_sequence A091705 A137215 A123336
Adjacent sequences: A091703 A091704 A091705 this_sequence A091707 A091708 A091709
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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 21 2005
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