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A267378 Primes of the form k^4 - k^2 + 7. 0
7, 19, 79, 607, 9907, 20599, 65287, 104659, 129967, 331207, 1047559, 1184839, 1872799, 3746167, 4098607, 6762607, 7308919, 11313139, 20146639, 21376759, 28392919, 43040167, 54693427, 59961799, 84925447, 104050207, 108232819, 131068159, 168883027, 187375039 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

From Robert Israel, Jan 18 2016: (Start)

Subset of A005471.

All terms == 7 or 19 (mod 30). (End)

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

k = 5: 5^4-5^2+7=607 (is prime).

MAPLE

select(isprime, [seq(x^4-x^2+7, x=1..1000)]); # Robert Israel, Jan 18 2016

MATHEMATICA

Select[Table[k^4 - k^2 + 7, {k, 100}], PrimeQ] (* Michael De Vlieger, Jan 13 2016 *)

PROG

(MAGMA) [a: n in [1..150] | IsPrime(a) where a is n^4-n^2+7]; // Vincenzo Librandi, Jan 15 2016

(PARI) lista(nn) = for(n=1, nn, if(ispseudoprime(p=n^4-n^2+7), print1(p, ", "))); \\ Altug Alkan, Jan 15 2016

CROSSREFS

Cf. A005471.

Sequence in context: A269784 A237436 A300556 * A088988 A109879 A109880

Adjacent sequences:  A267375 A267376 A267377 * A267379 A267380 A267381

KEYWORD

nonn,easy

AUTHOR

Emre APARI, Jan 13 2016

EXTENSIONS

More terms from Vincenzo Librandi, Jan 15 2016

STATUS

approved

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Last modified January 25 14:40 EST 2022. Contains 350572 sequences. (Running on oeis4.)