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A133834 Numbers n such that primorial(n)^4 + 1 is prime. 0
1, 2, 4, 23, 76, 339, 1282 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Seven terms found and primes proved by PrimeForm ([N-1, Brillhart-Lehmer-Selfridge]). p(1282)#^4 + 1 has 18042 decimal digits. There are no more terms <= 2810.

LINKS

Table of n, a(n) for n=1..7.

EXAMPLE

As primorial(2)^4 + 1 = (3*2)^4 + 1 = 1297 is prime, 2 is a term.

CROSSREFS

Cf. A092061.

Sequence in context: A322520 A018279 A307459 * A203103 A308164 A173352

Adjacent sequences:  A133831 A133832 A133833 * A133835 A133836 A133837

KEYWORD

hard,nonn

AUTHOR

Rick L. Shepherd, Sep 26 2007

STATUS

approved

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Last modified February 20 04:49 EST 2020. Contains 332063 sequences. (Running on oeis4.)