A121619 Indices n such that Nexus numbers of order 7 (A022523(n-1) = n^7 - (n-1)^7) are primes.

2, 4, 7, 8, 9, 10, 12, 17, 26, 33, 36, 39, 41, 49, 51, 55, 59, 66, 78, 79, 80, 88, 96, 98, 104, 113, 118, 120, 123, 135, 136, 142, 146, 156, 157, 160, 162, 173, 176, 194, 210, 219, 220, 221, 222, 224, 232, 234, 247, 281, 291, 297, 298, 305

Offset: 1

Author

Alexander Adamchuk, Aug 10 2006

Keywords

• nonn

Comments

Corresponding Nexus primes of order 7 (or primes of form A022523(n-1) = n^7 - (n-1)^7) are listed in A121618[n] = {127, 14197, 543607, 1273609, 2685817, 5217031, 16344637, 141903217,...}.

Links

• Vladimir Pletser, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A022523, A121619, A121618, A121616, A121620.

Programs

Mathematica

t = {}; Do[np7 = n^7 - (n - 1)^7; If[PrimeQ[np7], AppendTo[t, n]], {n, 305}]; t (* Carl R. White, Feb 28 2008 *)
Flatten[Position[Partition[Range[400]^7,2,1],?(PrimeQ[#[[2]]- #[[1]]]&), {1}, Heads->False]]+1 (* or *) Select[Range[400],PrimeQ[#^7-(#-1)^7]&] (* _Harvey P. Dale, Mar 19 2017 *)

Extensions

More terms from Carl R. White, Feb 28 2008