OFFSET
1,1
COMMENTS
The Euler polynomial x^2 + x + 41 gives primes for consecutive x from 0 to 39.
For numbers x for which x^2 + x + 41 is not prime see A007634.
Let P(x)=x^2 + x + 41. In view of identity P(x+P(x))=P(x)*P(x+1), all values of P(x+P(x)) are in the sequence. - Vladimir Shevelev, Jul 16 2012
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
FORMULA
a(n) ~ n^2. [Charles R Greathouse IV, Dec 08 2011]
MATHEMATICA
a = {}; Do[If[PrimeQ[x^2 + x + 41], null, AppendTo[a, x^2 + x + 41]], {x, 0, 500}]; a
Select[Table[x^2+x+41, {x, 200}], CompositeQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 21 2018 *)
PROG
(Haskell)
a145292 n = a145292_list !! (n-1)
a145292_list = filter ((== 0) . a010051) a202018_list
-- Reinhard Zumkeller, Dec 09 2011
(PARI) for(n=1, 1e3, if(!isprime(t=n^2+n+41), print1(t", "))) \\ Charles R Greathouse IV, Dec 08 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Oct 06 2008
STATUS
approved