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A105182 Numbers k such that 2^(2*(k+1)) + 2^k + 1 is prime. 1
1, 5, 9, 49, 61, 81, 149, 413, 485, 661, 709, 1337, 2885, 2925, 3013, 7213, 9669, 10245 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

Steven Harvey, Inverse Carol Primes

EXAMPLE

2^4 + 2^1 + 1 = 19 is prime so a(1)=1.

2^12 + 2^5 + 1 = 4129 is prime so a(2)=5.

PROG

(PARI) is(n)=ispseudoprime(2^(2*(n+1))+2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

(MAGMA) [k: k in [0..200] | IsPrime(2^(2*(k+1))+2^k+1)]; // Jinyuan Wang, Mar 20 2020

CROSSREFS

Cf. A105181.

Sequence in context: A149502 A219701 A088974 * A100457 A080872 A328333

Adjacent sequences:  A105179 A105180 A105181 * A105183 A105184 A105185

KEYWORD

nonn,more

AUTHOR

Pierre CAMI, Apr 11 2005

EXTENSIONS

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008

STATUS

approved

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Last modified October 19 14:40 EDT 2021. Contains 348090 sequences. (Running on oeis4.)