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A117842
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Partial sum of smallest prime >= n (A007918).
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1
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2, 4, 6, 9, 14, 19, 26, 33, 44, 55, 66, 77, 90, 103, 120, 137, 154, 171, 190, 209, 232, 255, 278, 301, 330, 359, 388, 417, 446, 475, 506, 537, 574, 611, 648, 685, 722, 759, 800, 841, 882, 923, 966, 1009, 1056, 1103, 1150, 1197, 1250, 1303, 1356
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OFFSET
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0,1
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COMMENTS
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Bertrand's [1845] postulate as proved by Chebyshev [1850] is versified: "Chebyshev said it, but I'll say it again; There's always a prime between n and 2n." [N. J. Fine in Schechter, 1998]. This sequence is the partial sum of the least such primes. It differs from A007504 "sum of first n primes" because of the repetitions in A007918.
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REFERENCES
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Schechter, B., My Brain is Open: The Mathematical Journeys of Paul Erdős. New York: Simon and Schuster, 1998.
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LINKS
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FORMULA
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a(n) = SUM[i=0..n] A007918(n). a(n) = SUM[i=0..n] smallest prime >= i. a(n) = SUM[i=0..n] nextprime(i).
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EXAMPLE
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a(50) = 2+ 2+ 2+ 3+ 5+ 5+ 7+ 7+ 11+ 11+ 11+ 11+ 13+ 13+ 17+ 17+ 17+ 17+ 19+ 19+ 23+ 23+ 23+ 23+ 29+ 29+ 29+ 29+ 29+ 29+ 31+ 31+ 37+ 37+ 37+ 37+ 37+ 37+ 41+ 41+ 41+ 41+ 43+ 43+ 47+ 47+ 47+ 47+ 53+ 53+ 53 = 1356.
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MAPLE
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ListTools:-PartialSums(map(nextprime, [$-1..100])); # Robert Israel, Aug 09 2020
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MATHEMATICA
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Accumulate[NextPrime[Range[0, 50]-1]] (* Harvey P. Dale, Nov 13 2022 *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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