A096723 - OEIS

A096723

Numbers n such that 3^n has the form 2p-+1 where p is prime.

1, 2, 3, 4, 7, 13, 16, 32, 64, 71, 103, 541, 1091, 1367, 1627, 4177, 9011, 9551, 36913, 43063, 49681, 57917, 483611, 877843, 2215303, 2704981, 3598867

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OFFSET

1,2

COMMENTS

For the corresponding primes p see A088553.

For n > 1, numbers n such that (3^n + (-1)^n)/2 is prime. - Thomas Ordowski, Dec 26 2016

LINKS

Table of n, a(n) for n=1..27.

MATHEMATICA

Select[Range[4200], Or@@PrimeQ[(3^#+{1, -1})/2]&] (* Harvey P. Dale, Mar 05 2013 *)

CROSSREFS

Cf. A028491, A075081, A088553, A093625, A171381.

Sequence in context: A200088 A004783 A031149 * A266498 A137495 A341531

Adjacent sequences: A096720 A096721 A096722 * A096724 A096725 A096726

KEYWORD

nonn,more

AUTHOR

Lekraj Beedassy, Jul 05 2004

EXTENSIONS

More terms from Ray Chandler, Jul 09 2004

a(25)-a(27) (from A028491 and A171381) from Tyler Busby, Mar 22 2023

STATUS

approved