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A271392 Integers n such that 3*n!!! + 1 is prime where n!!! is A007661(n). 1
2, 4, 5, 8, 9, 15, 16, 23, 27, 32, 34, 35, 38, 40, 46, 54, 57, 83, 87, 97, 162, 165, 223, 235, 282, 488, 503, 575, 673, 823, 857, 885, 965, 1112, 1401, 2288, 2569, 2788, 3133, 3539, 4070, 4654, 5020, 5613, 6720, 7773 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Corresponding primes are 7, 13, 31, 241, 487, 87481, 174721, 289027201, 21427701121, ...

LINKS

Table of n, a(n) for n=1..46.

EXAMPLE

4 is a term because 3*4!!! + 1 = 13 is prime.

CROSSREFS

Cf. A007661, A037083, A084438, A217647, A215779, A271396.

Sequence in context: A065300 A080403 A280050 * A195364 A279793 A305076

Adjacent sequences:  A271389 A271390 A271391 * A271393 A271394 A271395

KEYWORD

nonn,more

AUTHOR

Altug Alkan, Apr 06 2016

STATUS

approved

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Last modified May 26 00:08 EDT 2020. Contains 334613 sequences. (Running on oeis4.)