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Search: id:A117583
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| A117583 |
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For successive primes p, the number of ratios t(n)/(t(n)-1), where t(n)=n(n+1)/2 is the n-th triangular number, which factor into primes less than or equal to p. |
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+0
3
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| 0, 1, 3, 7, 9, 16, 22, 29, 35, 39, 50, 57, 68
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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As in the case of square numerators, triangular numerators of superparticular ratios m/(m-1) factorizable only up to a relatively small prime p are relatively common.
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REFERENCES
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E. F. Ecklund and R. B. Eggleton, Prime factors of consecutive integers, Amer. Math. Monthly, 79 (1972), 1082-1089.
D. H. Lehmer, On a problem of Stormer, Ill. J. Math., 8 (1964), 57-69.
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CROSSREFS
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Cf. A002071, A117582.
Sequence in context: A128539 A057463 A118258 this_sequence A126106 A064194 A036978
Adjacent sequences: A117580 A117581 A117582 this_sequence A117584 A117585 A117586
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KEYWORD
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hard,nonn
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AUTHOR
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Gene Ward Smith (genewardsmith(AT)gmail.com), Apr 02 2006
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