login
A087176
a(n) - 1 is the maximal number of integers for which the absolute value of a reducible polynomial with integral coefficients of degree n is a prime.
0
5, 6, 9, 9, 9, 10, 11
OFFSET
2,1
COMMENTS
I can prove a(n) < n+4 and am certain that a(n)=n+3 for n>6, but cannot prove it.
REFERENCES
Michael Golomb, "Prime numbers and Irreducible Polynomials", in a forthcoming issue (in 2003) of Mathematics Magazine
EXAMPLE
a(3)=6 because the polynomial (x^2 -x -1)( 6x + 11) equals 5,-11,-17,23,-5 at the integers -1,0,1,2,-2 resp., but no reducible polynomial of degree 3 can be of absolute value a prime at 6 integers.
CROSSREFS
Sequence in context: A332327 A260635 A306016 * A227006 A139454 A049329
KEYWORD
hard,nonn
AUTHOR
Michael Golomb (mgolomb(AT)math.purdue.edu), Oct 19 2003
STATUS
approved