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Search: id:A073513
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| A073513 |
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Number of primes less than 10^n with initial digit 5. |
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+0
1
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| 1, 3, 17, 131, 1055, 8615, 72951, 633932, 5602768, 50193913, 454577490, 4153943134, 38243708524, 354330372215, 3300752009165, 30892997367352, 290332329192655, 2738477783884855, 25913537508233527
(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)=3 because there are 3 primes up to 10^2 whose initial digit is 5 (namely 5, 53 and 59).
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MATHEMATICA
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f[n_] := f[n] = PrimePi[6*10^n] - PrimePi[5*10^n] + f[n - 1]; f[0] = 1; Table[ f[n], {n, 0, 13}]
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CROSSREFS
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Cf. A073509 to A073517, their sum is A006880.
Sequence in context: A093460 A089815 A006759 this_sequence A074524 A093986 A055214
Adjacent sequences: A073510 A073511 A073512 this_sequence A073514 A073515 A073516
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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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