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Search: id:A062311
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| A062311 |
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Number of ways writing n! as a sum of two primes. |
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+0
2
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| 0, 0, 0, 1, 3, 12, 39, 184, 951, 5531, 38713, 346207, 3130812, 34444964
(list; graph; listen)
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OFFSET
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0,5
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COMMENT
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Number of unordered pairs of primes (p,q) such that n! = p + q.
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FORMULA
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In other words, a(n) = A061358(n!) = number of prime+prime partitions of n!.
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EXAMPLE
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n = 4: 4! = 24 = 5+19 = 7+17 = 11+13 so a(4) = 3.
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CROSSREFS
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Cf. A061358, A000142. See A140088 for a variant.
Sequence in context: A123109 A110153 A122994 this_sequence A034956 A032093 A007993
Adjacent sequences: A062308 A062309 A062310 this_sequence A062312 A062313 A062314
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KEYWORD
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nonn,more
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Jul 05 2001
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EXTENSIONS
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a(9)-a(12) from Hans Havermann (pxp(AT)rogers.com), Apr 29 2008
34444964 from Graeme McRae (g_m(AT)mcraefamily.com), May 02 2008
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