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A153429
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Numbers n such that n! is equal to the sum of two consecutive primes.
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OFFSET
| 1,1
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COMMENTS
| 102 is the only known number n such that two numbers n!/2-(n+1) and n!/2+(n+1)
are consecutive primes.
No other terms below 1000. [From Max Alekseyev (maxale(AT)gmail.com), Feb 14 2009]
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LINKS
| Carlos Rivera Sum of k primes = Product of k integers
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EXAMPLE
| Representations as the sum of two consecutive primes: 4!=(4!/2-1)+(4!/2+1), 5!=(5!/2-1)+(5!/2+1), 27!=(27!/2-107)+(27!/2+107), 77!=(77!/2-397)+(77!/2+397), and 102!=(102!/2-103)+(102!/2+103).
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MATHEMATICA
| Get["NumberTheory`NumberTheoryFunctions`"];
Do[If[PreviousPrime[n!/2]+NextPrime[n!/2]==n!, Print[n]], {n, 700}]
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CROSSREFS
| Cf. A153430.
Sequence in context: A144053 A084465 A056200 * A092659 A002352 A042647
Adjacent sequences: A153426 A153427 A153428 * A153430 A153431 A153432
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KEYWORD
| more,nonn
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AUTHOR
| Farideh Firoozbakht (mymontain(AT)yahoo.com), Feb 07 2009
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EXTENSIONS
| Edited by Max Alekseyev (maxale(AT)gmail.com), Feb 07 2011
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