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A111504
Numbers k such that k^5 - k^3 - 1 and k^5 - k^3 + 1 are twin primes.
1
5, 6, 64, 210, 265, 364, 440, 475, 546, 625, 680, 785, 806, 839, 925, 930, 931, 951, 1044, 1091, 1105, 1224, 1226, 1559, 1636, 1651, 1699, 1835, 1850, 1966, 1995, 2120, 2295, 2309, 2511, 2541, 2655, 2984, 3100, 3501, 3680, 4159, 4444, 4474, 4580, 4606, 4755, 4779
OFFSET
1,1
LINKS
EXAMPLE
5^5 - 5^3 - 1 = 2999, 5^5 - 5^3 + 1 = 3001, and 2999 and 3001 are twin primes, so 5 is in the sequence.
MATHEMATICA
lst={}; Do[If[PrimeQ[n^5-n^3-1]&&PrimeQ[n^5-n^3+1], AppendTo[lst, n]], {n, 10^3}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 14 2008 *)
PROG
(Magma) [k: k in [1..4800]| IsPrime(a-1) and IsPrime(a+1) where a is k^5 - k^3]; // Marius A. Burtea, Jan 01 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Pierre CAMI, Nov 16 2005
EXTENSIONS
3 missing terms added by Amiram Eldar, Jan 01 2020
STATUS
approved