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A080778 Double factorial primes; values for which n!!+1 is prime. 23
0, 1, 2, 518, 33416, 37310, 52608, 123998 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..8.

Ken Davis, Status of Search for Multifactorial Primes.

Ken Davis, Results for n!2+1.

Eric Weisstein's World of Mathematics, Double Factorial Prime

Eric Weisstein's World of Mathematics, Integer Sequence Primes

CROSSREFS

A006882(n)+1 is prime.

Sequence in context: A196290 A182446 A218436 * A007513 A071613 A262649

Adjacent sequences:  A080775 A080776 A080777 * A080779 A080780 A080781

KEYWORD

hard,nonn

AUTHOR

Steven Harvey, Mar 11 2003

EXTENSIONS

a(7) from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008

a(8) from Sou Fukui, Jun 05 2015

STATUS

approved

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Last modified December 7 20:56 EST 2016. Contains 278895 sequences.