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Search: id:A074210
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| A074210 |
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Number of primes <= n is equal to the sum of primes from the smallest prime factor of n to the largest prime factor of n. |
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+0
1
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| 1, 4, 12, 30, 272, 4717, 5402, 18487, 20115, 28372, 33998, 111040, 115170, 456975, 821586, 1874660, 4029676, 4060029, 59497900, 232668002, 313128068, 529436220
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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No more terms through 20000000. - Ryan Propper (rpropper(AT)stanford.edu), Jun 03 2006
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EXAMPLE
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pi(272) = 58 and 272 = 2^4*17 and 2+3+5+7+11+13+17 = 58. ?
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MATHEMATICA
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Do[l = First /@ FactorInteger[n]; m = Range[First[l], Last[l]]; If[Plus @@ Select[m, PrimeQ] == PrimePi[n], Print[n]], {n, 2*10^7}] - Ryan Propper (rpropper(AT)stanford.edu), Jun 03 2006
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CROSSREFS
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Cf. A000720, A074036.
Sequence in context: A006802 A068055 A074252 this_sequence A005289 A037255 A027658
Adjacent sequences: A074207 A074208 A074209 this_sequence A074211 A074212 A074213
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KEYWORD
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more,nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Sep 19 2002
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EXTENSIONS
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More terms from Ryan Propper (rpropper(AT)stanford.edu), Jun 03 2006
a(19)-a(22) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Oct 12 2008
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