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Search: id:A159910
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| A159910 |
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Distance of prime quadruplets divided by 30, rounded towards the nearest integer. |
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+0
2
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| 0, 3, 3, 21, 22, 13, 7, 39, 7, 73, 126, 119, 88, 3, 11, 66, 29, 17, 53, 42, 101, 214, 104, 298, 252, 133, 255, 141, 76, 91, 168, 81, 45, 56, 203, 301, 43, 66, 291, 223, 92, 97, 442, 290, 437, 281, 38, 144, 549, 241, 29, 192, 11, 518, 266, 490, 122, 130, 13, 329, 85, 209
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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First differences of A007530, divided by 30 (and rounded to 0 for a(1)). The first prime quadruplet is the only one not starting at 11 (mod 30), and has no corresponding value in A014561. The "distance" can mean distance of starting points, or distance of barycenters, but also the distance in the strict sense (differing by 8 from the former), which gives the same value after rounding to the nearest integer.
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FORMULA
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a(n) = (A007530(n+1)-A007530(n))/30 = A014561(n)-A014561(n-1) for n>1.
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PROGRAM
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(PARI) A159910( n, list=0, s=5 )={ my(o, p, q, r); until(n--<0, o=s; until( p+8==s=nextprime(s+2), p=q; q=r; r=s); list & p>o & print1((s-o)\30, ", "); ); (s-o)\30}
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CROSSREFS
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Sequence in context: A078431 A112534 A006656 this_sequence A130723 A036114 A092864
Adjacent sequences: A159907 A159908 A159909 this_sequence A159911 A159912 A159913
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KEYWORD
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nonn
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AUTHOR
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M. F. Hasler (MHasler(AT)univ-ag.fr), May 04 2009
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