A194194 Primes of the form k^6 + k^5 + k^4 + k^3 + k^2 + k + 1 where k is nonprime.

7, 55987, 8108731, 321272407, 3092313043, 4201025641, 9684836827, 31401724537, 47446779661, 83925549247, 100343116693, 141276239497, 265462278481, 438668366137, 654022685443, 742912017121, 2333350772341, 3324554405047, 4033516174507, 4432676798593, 9752186278927, 14505760086637, 15656690128843, 16882733081761

Offset

1,1

Comments

Subset of A088550. The k in A018252 for which k^6 + k^5 + k^4 + k^3 + k^2 + k + 1 are prime begin 1, 6, 14, 26, 38, 40, ... = A288939.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

a(1) = 1^6 + 1^5 + 1^4 + 1^3 + 1^2 + 1 + 1 = 7.
a(2) = 6^6 + 6^5 + 6^4 + 6^3 + 6^2 + 6 + 1 = 55987.
a(3) = 14^6 + 14^5 + 14^4 + 14^3 + 14^2 + 14 + 1 = 8108731.
a(4) = 26^6 + 26^5 + 26^4 + 26^3 + 26^2 + 26 + 1 = 321272407.

Mathematica

With[{nn=200}, Select[Total[#^Range[0, 6]]&/@Complement[Range[nn], Prime[ Range[PrimePi[nn]]]], PrimeQ]] (* Harvey P. Dale, Nov 15 2013 *)

Crossrefs

Cf. A000040, A018252, A088548, A185632, A192321, A288939.

Sequence in context: A348643 A123062 A300201 * A110719 A068162 A158816

Adjacent sequences: A194191 A194192 A194193 * A194195 A194196 A194197

Keyword

nonn,easy

Author

Jonathan Vos Post, Dec 20 2012

Status

approved