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Search: id:A088982
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| A088982 |
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Primes that are between consecutive prime-indexed-primes. |
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+0
1
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| 7, 13, 19, 23, 29, 37, 43, 47, 53, 61, 71, 73, 79, 89, 97, 101, 103, 107, 113, 131, 137, 139, 149, 151, 163, 167, 173, 181, 193, 197, 199, 223, 227, 229, 233, 239, 251, 257, 263, 269, 271, 281, 293, 307, 311, 313, 317, 337, 347, 349, 359, 373, 379, 383, 389
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Conjecture: For x > 1 there is at least 1 prime between prime(prime(x) and prime(prime(x+1).
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FORMULA
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Prime p such that prime(prime(x)) < p < prime(prime(x+1)).
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EXAMPLE
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Prime(prime(4)) = 17 and prime(prime(5) = 31 and 19,23,29 are between 17 and 31, so 19, 23 and 29 are members.
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PROGRAM
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(PARI) pipprimes(n) = { for(x=1, n, c=-2; p1 = prime(prime(x)); p2 = prime(prime(x+1)); forprime(y=p1, p2, c++; if(y > p1 && y < p2, print1(y", ")); ); ) }
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CROSSREFS
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See A007821 for a similar sequence.
Sequence in context: A092409 A124095 A109369 this_sequence A033561 A049591 A058620
Adjacent sequences: A088979 A088980 A088981 this_sequence A088983 A088984 A088985
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KEYWORD
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nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Oct 31 2003
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