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Search: id:A116999
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| A116999 |
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Numbers n such that 2^n - prime(n)^2 is prime. |
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+0
1
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| 11, 15, 17, 23, 27, 47, 231, 457, 1249, 1529, 2343, 4693, 5939, 5997, 8367, 19855, 21295
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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No more terms below 30000. - Giovanni Resta (g.resta(AT)iit.cnr.it), Apr 03 2006
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EXAMPLE
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15 is in the sequence because the 15th prime is 47 and 2^15-47^2=30559 is prime.
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MAPLE
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a:=proc(n) if isprime(2^n-ithprime(n)^2)=true then n else fi end: seq(a(n), n=1..1600); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 06 2006
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PROGRAM
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(PARI) for(i=1, 2000, if(isprime(2^i-prime(i)^2), print1(i, ", ")))
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CROSSREFS
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Sequence in context: A139065 A111322 A069822 this_sequence A053675 A031944 A049354
Adjacent sequences: A116996 A116997 A116998 this_sequence A117000 A117001 A117002
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KEYWORD
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hard,more,nonn
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AUTHOR
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Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Apr 03 2006
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EXTENSIONS
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Corrected and extended by Giovanni Resta (g.resta(AT)iit.cnr.it), Apr 03 2006
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