OFFSET
1,1
COMMENTS
Note that there are no primes of the form n^3 + n^2 + n + 1 = (n+1)*(n^2+1) as irreducible components over Z.
From Bernard Schott, May 15 2017: (Start)
These are the primes associated with A286094.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Bernard Schott, Les nombres brésiliens, Reprinted from Quadrature, no. 76, avril-juin 2010, pages 30-38.
FORMULA
{n^4 + n^3 + n^2 + n + 1 where n is in A018252}.
EXAMPLE
a(1) = 1^4 + 1^3 + 1^2 + 1 + 1 = 5.
a(2) = 12^4 + 12^3 + 12^2 + 12 + 1 = 22621.
MAPLE
for n from 1 to 150 do p(n):= 1+n+n^2+n^3+n^4;
if tau(n)>2 and isprime(p(n)) then print(n, p(n)) else fi od: # Bernard Schott, May 15 2017
MATHEMATICA
Select[Map[Total[#^Range[0, 4]] &, Select[Range@ 204, ! PrimeQ@ # &]], PrimeQ] (* Michael De Vlieger, May 15 2017 *)
PROG
(PARI) print1(5); forcomposite(n=4, 1e3, if(isprime(t=n^4+n^3+n^2+n+1), print1(", "t))) \\ Charles R Greathouse IV, Mar 25 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jonathan Vos Post, Dec 20 2012
STATUS
approved