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Search: id:A073511
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| A073511 |
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Number of primes less than 10^n with initial digit 7. |
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+0
1
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| 1, 4, 18, 125, 1027, 8435, 71564, 622882, 5516130, 49495432, 448855139, 4106164356, 37838546363, 350849788546, 3270531245684, 30628143485953, 287992070079777, 2717649138419586, 25726964404879666
(list; graph; listen)
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OFFSET
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1,2
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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)=4 because there are 4 primes up to 10^2 whose initial digit is 7 (namely 7, 71, 73 and 79).
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MATHEMATICA
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f[n_] := f[n] = PrimePi[8*10^n] - PrimePi[7*10^n] + f[n - 1]; f[0] = 1; 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: A005442 A084661 A112294 this_sequence A108704 A001423 A158341
Adjacent sequences: A073508 A073509 A073510 this_sequence A073512 A073513 A073514
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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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