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Search: id:A075410
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| A075410 |
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a(n) is the smallest m such that n!!-m and n!!+m are both primes. |
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3
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| 0, 0, 3, 2, 5, 2, 5, 8, 7, 4, 19, 16, 29, 68, 97, 16, 109, 86, 19, 158, 17, 172, 41, 16, 529, 106, 263, 212, 163, 302, 593, 302, 607, 262, 311, 428, 227, 106, 1271, 8, 229, 386, 1489, 32, 47, 1996, 1097, 2566, 41, 632, 1913, 458, 149, 1244, 2837, 362, 3317, 908
(list; graph; listen)
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OFFSET
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2,3
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COMMENT
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For n = 5,7,10,11,22,41,67,76,91,96,163,245,299,341, n!! is an interprime, the average of two consecutive primes, see A075275. See also n^n and n! as average of two primes in A075468 and A075409.
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EXAMPLE
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a(4) = 3 because 4!! = 8 and 8 -/+ 3 = 5 and 11 are primes with smallest equal distances from 4!!
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CROSSREFS
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Cf. A075275, A075468 and A075409.
Sequence in context: A112528 A154421 A057034 this_sequence A023513 A069735 A046524
Adjacent sequences: A075407 A075408 A075409 this_sequence A075411 A075412 A075413
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), Sep 18 2002
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EXTENSIONS
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More terms from David Wasserman (dwasserm(AT)earthlink.net), Jan 17 2005
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