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Search: id:A065917
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| A065917 |
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Boundaries of primorial intervals [1,3]; [3,9],[9,15]; [15,45], etc. |
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+0
2
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| 1, 3, 9, 15, 45, 75, 105, 315, 525, 735, 945, 1155, 3465, 5775, 8085, 10395, 12705, 15015, 45045, 75075, 105105, 135135, 165165, 195195, 225225, 255255, 765765, 1276275, 1786785, 2297295, 2807805, 3318315, 3828825, 4339335, 4849845
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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a(n+1)= a(n)+q(j) for primorial q(j) < a(n+1) <= q(j+1)/2.
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EXAMPLE
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a(4)= 15= a(3)+q(2)= 9+ 6, a(7)= 105= a(6)+q(3)= 75+ 30,
a(5)= 45= a(4)+q(3)=15+30, a(8)= 315= a(7)+q(4)=105+210.
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CROSSREFS
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Primorial q(j)= A002110(j), interval count A005521(j+1)-1.
Sequence in context: A133997 A057909 A082702 this_sequence A053624 A119239 A140864
Adjacent sequences: A065914 A065915 A065916 this_sequence A065918 A065919 A065920
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KEYWORD
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nonn,easy
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AUTHOR
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Frank.Ellermann(AT)t-online.de, Dec 08 2001
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