A241265 Numbers n such that n^4+(n+1)^4 is not prime.

5, 7, 10, 11, 15, 17, 18, 19, 20, 21, 22, 23, 24, 28, 29, 30, 32, 35, 39, 41, 42, 44, 45, 46, 47, 49, 50, 51, 52, 53, 55, 56, 57, 58, 59, 60, 61, 62, 64, 65, 66, 69, 70, 71, 73, 75, 76, 77, 79, 80, 81, 83, 84, 85, 86, 90, 91, 92, 93, 94, 95, 96, 99, 100, 101

Offset: 1

Author

Vincenzo Librandi, Apr 20 2014

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Complement of A155211.

Programs

Magma

[n: n in [1..200] | not IsPrime(n^4+(n+1)^4)];

Mathematica

Select[Range[200], ! PrimeQ[#^4 + (# + 1)^4] &]
Position[Total/@Partition[Range[120]^4,2,1],?CompositeQ]//Flatten (* _Harvey P. Dale, Mar 31 2024 *)

Formula

7 is in this sequence because 7^4+8^4 = 6497 = 73*89.