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Search: id:A054656
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| A054656 |
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Number of primes <=n which do not appear in any partitions of n into distinct primes. |
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1
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| 0, 0, 0, 1, 2, 0, 3, 1, 2, 2, 0, 4, 1, 3, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 2, 0, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 2
(list; graph; listen)
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OFFSET
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0,5
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COMMENT
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Conjecture: if n >= 23 then a(n)=2 if both (n-6) and (n-4) are prime, a(n)=1 if one of (n-6), (n-4) or (n-1) is prime, a(n)=0 otherwise
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EXAMPLE
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a(22)=1 since 22=2+7+13=2+3+17=5+17=3+19, so the primes 2,3,5,7,13,17 and 19 appear at least once but 11 does not.
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CROSSREFS
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Cf. A000586.
Sequence in context: A078804 A071465 A051709 this_sequence A080096 A068915 A133925
Adjacent sequences: A054653 A054654 A054655 this_sequence A054657 A054658 A054659
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KEYWORD
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nonn
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AUTHOR
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Henry Bottomley (se16(AT)btinternet.com), Apr 17 2000
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