A241268 Numbers n such that (n+1)^7-n^7 is not prime.

2, 4, 5, 10, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30, 31, 33, 34, 36, 37, 39, 41, 42, 43, 44, 45, 46, 47, 49, 51, 52, 53, 55, 56, 57, 59, 60, 61, 62, 63, 64, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 80, 81, 82, 83, 84, 85, 86, 88

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

Example

4 is in this sequence because 5^7 - 4^7 = 61741 = 29*2129.

Mathematica

Select[Range[100], ! PrimeQ[(# + 1)^7 - #^7] &]

Prog

(Magma) [n: n in [0..350] | not IsPrime((n+1)^7-n^7)];

Crossrefs

Complement of A113826.

Sequence in context: A083416 A022770 A141481 * A285697 A047611 A325095

Adjacent sequences: A241265 A241266 A241267 * A241269 A241270 A241271

Keyword

nonn,easy

Author

Vincenzo Librandi, Apr 20 2014

Status

approved