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A053706 Primes p such that between p and the next prime, 2 prime powers (A025475) occur. 1
7, 23, 113, 2179, 32749 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

No other terms < 4290000000. - Jud McCranie, Jun 20 2000

There are no other terms < 2^63. - Donovan Johnson, Mar 11 2013

LINKS

Table of n, a(n) for n=1..5.

EXAMPLE

Between 7 and 11 the 2 prime powers are 8 and 9, between 23 and 29 the 2 prime powers are 25 and 27, between 113 and 127 the 2 prime powers are 121 and 125, while between 32749 and 32771 the 2 prime powers are 32761 = 181^2 and 32768 = 2^15.

PROG

(PARI) isok(p) = isprime(p) && (q=nextprime(p+1)) && (v=vector(q-p, x, p+x)) && (#select(x->(isprimepower(x) && !isprime(x)), v) == 2);

lista(nn) = forprime(p=2, nn, if (isok(p), print1(p, ", "))); \\ Michel Marcus, Jul 15 2017

CROSSREFS

Cf. A025475, A053607.

Sequence in context: A096327 A267805 A154113 * A137367 A267926 A228698

Adjacent sequences:  A053703 A053704 A053705 * A053707 A053708 A053709

KEYWORD

more,nonn

AUTHOR

Labos Elemer, Feb 14 2000

EXTENSIONS

Corrected by James A. Sellers, Feb 22 2000

STATUS

approved

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Last modified August 21 23:04 EDT 2019. Contains 326169 sequences. (Running on oeis4.)