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A073516
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Number of primes less than 10^n with initial digit 2.
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0
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1, 3, 19, 146, 1129, 9142, 77025, 664277, 5837665, 52064915, 469864125, 4281198201, 39319600765, 363545360347, 3380562309312, 31590949437540, 296487794277035, 2793170342851930, 26402713858800478, 250324979315879678
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..20.
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 2 (namely 2, 23 and 29).
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MATHEMATICA
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f[n_] := f[n] = PrimePi[3*10^n] - PrimePi[2*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: A058859 A095002 A080833 * A005258 A131551 A074546
Adjacent sequences: A073513 A073514 A073515 * A073517 A073518 A073519
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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, Aug 29 2002
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STATUS
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approved
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