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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 (list; graph; refs; listen; history; internal format)
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: A197283 A118261 A021641 * A049329 A195925 A188191

Adjacent sequences:  A087173 A087174 A087175 * A087177 A087178 A087179

KEYWORD

hard,nonn

AUTHOR

Michael Golomb (mgolomb(AT)math.purdue.edu), Oct 19 2003

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Last modified February 16 21:51 EST 2012. Contains 205978 sequences.