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.
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
Keywords
Links
- Robert Israel, Table of n, a(n) for n = 1..1000
Programs
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Haskell
a219117_list = filter (all (== 1) . p) [1..] where p x = map (a010051 . (+ (x + 1)) . (x ^)) [1..4]
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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