OFFSET
1,1
COMMENTS
Since n^4 - n^3 - n - 1 = (n^2 + 1)*(n^2 - n - 1), these are also numbers n such that n^2 + 1 and n^2 - n - 1 are both prime. Numbers in the intersection of A005574 and A002328. - Derek Orr, Aug 10 2014 [Sequence numbers corrected by Jens Kruse Andersen, Aug 11 2014]
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..400
MATHEMATICA
Select[Range[2000], PrimeOmega[#^4 - #^3 - # - 1]==2 &]
PROG
(Magma) IsSemiprime:=func<n | &+[ k[2]: k in Factorization(n) ] eq 2 >; [ n: n in [2..1500] | IsSemiprime(n^4 - n^3 - n - 1)];
(PARI) for(n=1, 10^4, if(isprime(n^2+1)&&isprime(n^2-n-1), print1(n, ", "))) \\ Derek Orr, Aug 10 2014
CROSSREFS
KEYWORD
nonn,less
AUTHOR
Vincenzo Librandi, Aug 10 2014
STATUS
approved