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A227446 Numbers k such that 7*2^(2*k)-5*2^kn+1 is prime. 0
0, 1, 3, 13, 39, 539, 2631, 4283 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(9) > 10000. - Jinyuan Wang, Feb 12 2019

LINKS

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

Eric L. F. Roettger, A Cubic Extension of the Lucas Functions, Ph. D. Dissertation, Dept. Math. and Statistics, Univ. Calgary, 2009 (see page 196).

MAPLE

select(isprime, [seq(7*2^(2*n)-5*2^n+1, n=0..1000)]); # Jinyuan Wang, Feb 12 2019

MATHEMATICA

Select[Range[0, 3000], PrimeQ[7 2^(2 #) - 5 2^# + 1]&]

PROG

(PARI) for(n=0, 10^6, if(ispseudoprime(7*2^(2*n)-5*2^n+1), print1(n, ", "))); \\ Joerg Arndt, Jul 14 2013

CROSSREFS

Cf. A058593.

Sequence in context: A167910 A147042 A018492 * A059020 A290720 A289654

Adjacent sequences:  A227443 A227444 A227445 * A227447 A227448 A227449

KEYWORD

nonn,more

AUTHOR

Vincenzo Librandi, Jul 14 2013

EXTENSIONS

a(8) from Jinyuan Wang, Feb 12 2019

STATUS

approved

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Last modified September 21 07:08 EDT 2019. Contains 327253 sequences. (Running on oeis4.)