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Search: id:A073508
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| A073508 |
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Number of primes == 9 (mod 10) less than 10^n. |
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+0
4
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| 0, 5, 38, 303, 2390, 19593, 166032, 1440186, 12711333, 113761326
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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This and the related sequences A073505-A073517 and A002280, A073548-A073565 are included because there is interest in the distribution of primes by their initial or final digits.
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LINKS
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Eric Weisstein's World of Mathematics, Modular Prime Counting Function
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EXAMPLE
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a(2)=5 because there are 5 primes == 9 (mod 10) less than 10^2. They are 19, 29, 59, 79 and 89.
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MATHEMATICA
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c = 0; k = 9; Do[While[k < 10^n, If[PrimeQ[k], c++ ]; k += 10]; Print[c], {n, 1, 10}]
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CROSSREFS
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Cf. A073509 to A073517. A073505(n) + A073506(n) + A073507(n) + A073508(n) + 1 = A006880(n).
Sequence in context: A027323 A110079 A110082 this_sequence A113207 A158266 A098937
Adjacent sequences: A073505 A073506 A073507 this_sequence A073509 A073510 A073511
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KEYWORD
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base,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 by Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 03 2002
a(10) from Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 22 2003
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