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Search: id:A073509
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| A073509 |
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Number of primes less than 10^n with initial digit 9. |
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+0
13
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| 0, 1, 15, 127, 1006, 8230, 70320, 614821, 5453140, 48982456, 444608278, 4070532710, 37535715441, 348245215460, 3247889171908, 30429496751905, 286235215995588, 2702000272361599, 25586688305447928
(list; graph; listen)
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OFFSET
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1,3
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LINKS
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Thomas R. Nicely, Some Results of Computational Research in Prime Numbers
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EXAMPLE
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a(2) = 1 because there is 1 prime less than 100 whose initial digit is 9 i.e. 97.
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MATHEMATICA
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f[n_] := f[n] = PrimePi[10^(n + 1)] - PrimePi[9*10^n] + f[n - 1]; f[0] = 0; Table[f[n], {n, 0, 12}]
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CROSSREFS
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Cf. A073509 to A073517, their sum is A006880.
Sequence in context: A071080 A069975 A027779 this_sequence A127595 A056579 A156922
Adjacent sequences: A073506 A073507 A073508 this_sequence A073510 A073511 A073512
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KEYWORD
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base,hard,nonn
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AUTHOR
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Shyam Sunder Gupta (guptass(AT)rediffmail.com), Aug 14 2002
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 29 2002
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