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A096178 Primes of the form primorial(p)/2+2. 4
3, 5, 17, 107, 15017, 3234846617, 100280245067, 3710369067407, 307444891294245707, 961380175077106319537, 139867498408927468089138080936033904837498617 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes of the form A070826(n)+2.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..18

FORMULA

a(n) = A070826(A096177(n)) + 2. - Amiram Eldar, Dec 26 2019

EXAMPLE

a(4) = 107 because 107 is a prime of the form primorial(7)/2 + 2 = A070826(4) + 2 = 2*3*5*7/2 + 2.

PROG

(PARI) for(n=1, 30, p=prod(k=1, n, prime(k))/2+2; if(ispseudoprime(p), print1(p, ", "))) \\ Hugo Pfoertner, Dec 26 2019

CROSSREFS

Cf. A070826, A096177 (primorial(p)/2+2 is prime), A096547 (primorial(p)/2-2 is prime), A067024 (smallest p+2 that has n distinct prime factors), A014545 (primorial primes), A087398.

Sequence in context: A191222 A084723 A288376 * A107312 A083213 A171271

Adjacent sequences:  A096175 A096176 A096177 * A096179 A096180 A096181

KEYWORD

nonn

AUTHOR

Hugo Pfoertner, Jun 27 2004

EXTENSIONS

a(1) inserted by Amiram Eldar, Dec 26 2019

STATUS

approved

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Last modified January 29 16:58 EST 2020. Contains 331347 sequences. (Running on oeis4.)