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A088987 Triples of primes between two consecutive prime-indexed primes. 0
19, 23, 29, 43, 47, 53, 71, 73, 79, 163, 167, 173, 193, 197, 199, 337, 347, 349, 409, 419, 421, 521, 523, 541, 569, 571, 577, 601, 607, 613, 719, 727, 733, 971, 977, 983, 1181, 1187, 1193, 1423, 1427, 1429, 1451, 1453, 1459, 1789, 1801, 1811, 2029, 2039, 2053 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Conjecture: There cannot be an even number total of primes between two consecutive prime-indexed primes.

The conjecture is true except for the first two prime-indexed primes (3 and 5), which have zero primes between them.

LINKS

Table of n, a(n) for n=1..51.

EXAMPLE

prime(prime(4)) = 17, prime(prime(5)) = 31. 19,23,29 are the "only" three primes between 17 and 31.

PROG

(PARI) pipprimes(n, m) = { for(x=1, n, c=0; p1 = prime(prime(x)); p2 = prime(prime(x+1)); forprime(y=p1+2, p2-2, c++); if(c==m, forprime(y=p1+2, p2-2, print1(y", "); ); ) ) }

CROSSREFS

Sequence in context: A286415 A305835 A019384 * A217281 A322960 A019360

Adjacent sequences:  A088984 A088985 A088986 * A088988 A088989 A088990

KEYWORD

nonn

AUTHOR

Cino Hilliard, Oct 31 2003

EXTENSIONS

Edited by T. D. Noe, Apr 14 2009

STATUS

approved

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Last modified October 26 06:08 EDT 2021. Contains 348257 sequences. (Running on oeis4.)