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Search: id:A031131
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| A031131 |
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Difference between n-th prime and (n+2)nd prime. |
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+0
21
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| 3, 4, 6, 6, 6, 6, 6, 10, 8, 8, 10, 6, 6, 10, 12, 8, 8, 10, 6, 8, 10, 10, 14, 12, 6, 6, 6, 6, 18, 18, 10, 8, 12, 12, 8, 12, 10, 10, 12, 8, 12, 12, 6, 6, 14, 24, 16, 6, 6, 10, 8, 12, 16, 12, 12, 8, 8, 10, 6, 12, 24, 18, 6, 6, 18, 20, 16, 12, 6, 10, 14, 14, 12, 10, 10, 14, 12, 12, 18, 12, 12, 12
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Distance between the pair of primes adjacent to the (n+1)-st prime. - Lekraj Beedassy (blekraj(AT)yahoo.com), Oct 01 2004 [Typo corrected by Zak Seidov, Feb 22 2009]
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..10000
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FORMULA
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a(n) = A001223(n) + A001223(n-1). - Lior Manor (lior.manor(AT)gmail.com) Jan 19 2005
Prime(n+2)-prime(n).
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EXAMPLE
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a(10)=8 because the 10-th prime=29 is bounded by primes (23,31) separated by a gap 8.
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MATHEMATICA
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Differences[lst_]:=Drop[lst, 2]-Drop[lst, -2]; Differences[Prime[Range[123]]] [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Aug 13 2009]
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PROGRAM
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(Mupad) ithprime(i+2)-ithprime(i) $ i = 1..65 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 26 2007
(SAGE) BB = primes_first_n(67) list = [] for i in range(65): list.append(BB[2+i]-BB[i]) list - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 14 2007
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CROSSREFS
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Sum of consecutive terms of A001223.
Cf. A031132, A031133, A031134, A122412, A122413.
Cf. A075527 (allowing 1 to be prime)
Sequence in context: A001177 A053991 A033957 this_sequence A105321 A160095 A135319
Adjacent sequences: A031128 A031129 A031130 this_sequence A031132 A031133 A031134
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KEYWORD
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nonn
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AUTHOR
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Jeff Burch (jmburch(AT)osprey.smcm.edu)
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EXTENSIONS
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Corrected by T. D. Noe (noe(AT)sspectra.com), Sep 11 2008
Edited by N. J. A. Sloane (njas(AT)research.att.com), Sep 18 2008 at the suggestion of T. D. Noe
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