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A219117
Numbers n such that n^1+n+1, n^2+n+1, n^3+n+1 and n^4+n+1 are all prime.
4
1, 2, 5, 6, 69, 131, 426, 1665, 2129, 2696, 5250, 7929, 9689, 13545, 14154, 14286, 16434, 19760, 25739, 27809, 29631, 36821, 41819, 46619, 48321, 59030, 60500, 61955, 62321, 73610, 77685, 79646, 80535, 82655, 85251, 86996, 91014, 96566, 97739, 105939, 108240
OFFSET
1,2
LINKS
MAPLE
select(t -> andmap(isprime, [2*t+1, t^2+t+1, t^3+t+1, t^4+t+1]), [$1..2*10^5]); # Robert Israel, Dec 15 2017
PROG
(Haskell)
a219117_list = filter (all (== 1) . p) [1..] where
p x = map (a010051 . (+ (x + 1)) . (x ^)) [1..4]
CROSSREFS
Cf. A057683 (subsequence); A010051.
Sequence in context: A055877 A288799 A281378 * A111190 A244434 A176007
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Nov 12 2012
STATUS
approved