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A070523 Cyclotomic[n, Prime[n]] is a prime number. 1
3, 6, 7, 14, 19, 31, 34, 66, 93, 307, 402, 421, 600, 848, 1022, 1057, 1906 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Values corresponding to a(3)=7 through a(13)=600 have been certified prime with Primo. Their sizes in decimal digits are 8, 10, 33, 64, 35, 51, 162, 1012, 455, 1455 and 584, respectively. Values corresponding to a(14) through a(17) are probable primes with lengths 1588, 1689, 3535 and 4014 decimal digits. a(18)>2000. - Rick L. Shepherd, Jul 10 2002

LINKS

Table of n, a(n) for n=1..17.

EXAMPLE

n=7: C[7, x]=1+x+xx+xxx+xxxx+xxxxx+xxxxxx at x=p(7)=17 gives a prime 25646167.

PROG

(PARI) for(n=1, 2000, x=prime(n); if(isprime(eval(polcyclo(n))), print1(n, ", ")))

CROSSREFS

Cf. A070518-A070522.

Sequence in context: A037015 A138218 A056055 * A233757 A139247 A124611

Adjacent sequences:  A070520 A070521 A070522 * A070524 A070525 A070526

KEYWORD

nonn,more

AUTHOR

Labos Elemer, May 02 2002

EXTENSIONS

More terms from Rick L. Shepherd, Jul 10 2002

STATUS

approved

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Last modified November 13 15:41 EST 2019. Contains 329106 sequences. (Running on oeis4.)