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 A227446 Numbers k such that 7*2^(2*k) - 5*2^k + 1 is prime. 0
 0, 1, 3, 13, 39, 539, 2631, 4283, 13595 (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..9. 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 a(9) from Michael S. Branicky, Apr 23 2023 STATUS approved

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Last modified June 18 01:32 EDT 2024. Contains 373468 sequences. (Running on oeis4.)