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Search: id:A064915
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| A064915 |
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Positive integers n that are not of the form p + q * a^2, where p and q are primes and a is the smallest prime not dividing n. |
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+0
2
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| 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 22, 24, 26, 28, 30, 36, 42, 48, 54, 60, 66, 72, 77, 84, 90, 96, 102, 108, 114, 120, 126, 174, 180, 210, 240, 270, 300, 330, 420, 630, 840, 1050, 1260
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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There are no other terms up to 10^7. Conjecture: There are no more terms in the sequence.
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MATHEMATICA
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rep[ n_ ] := Module[ {a, q}, For[ a=2, GCD[ n, a ]!=1, a++, Null ]; For[ q=2, q a^2<n, q++, If[ PrimeQ[ q ]&&PrimeQ[ n-q a^2 ], Return[ True ] ] ]; False ]; Select[ Range[ 1, 10000 ], !rep[ # ]& ]
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CROSSREFS
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Cf. A064653.
Sequence in context: A130232 A103969 A030141 this_sequence A120003 A036965 A133184
Adjacent sequences: A064912 A064913 A064914 this_sequence A064916 A064917 A064918
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KEYWORD
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nonn
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AUTHOR
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Dean Hickerson (dean.hickerson(AT)yahoo.com), Oct 13 2001
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