OFFSET
0,1
COMMENTS
A "prime-generating" polynomial: This polynomial generates 88 distinct primes for n from 0 to 99, just two primes fewer than the record held by the polynomial discovered by N. Boston and M. L. Greenwood, that is 41*n^2 - 4641*n + 88007 (this polynomial is sometimes cited as 41*n^2 + 33*n - 43321, which is the same for the input values [-57, 42], see the references below).
The nonprime terms in the first 100 are: 10961 = 97*113; 10547 = 53*199; 9353 = 47*199; 7181 = 43*167; 6847 = 41*167; 5893 = 71*83; 3233 = 53*61; 2021 = 43*47; 1681 = 41^2; 1763 = 41*43; 2491 = 47*53; 4331 = 61*71.
For n = m + 41 we obtain the polynomial 4*m^2 - 154*m + 1523, which generates 40 primes in a row starting from m=0 (polynomial already reported, see the link below).
REFERENCES
W. Narkiewicz, The Development of Prime Number Theory: from Euclid to Hardy and Littlewood, Springer Monographs in Mathematics, 2000, page 43.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
R. A. Mollin, Prime-Producing Quadratics, The American Mathematical Monthly, Vol. 104, No. 6 (1997), pp. 529-544.
Carlos Rivera, Puzzle 232: Primes and Cubic polynomials, The Prime Puzzles & Problems Connection.
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
a(n) = 4*n^2 - 482*n + 14561.
G.f.: (-15047*x^2+29600*x-14561)/(x-1)^3. - Alexander R. Povolotsky, Jun 21 2012
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - G. C. Greubel, Feb 26 2017
MATHEMATICA
Table[4n^2-482n+14561, {n, 0, 41}] (* Harvey P. Dale, Sep 09 2014 *)
LinearRecurrence[{3, -3, 1}, {14561, 14083, 13613}, 50] (* or *) CoefficientList[Series[ (-15047*x^2+29600*x-14561)/(x-1)^3, {x, 0, 50}], x] (* G. C. Greubel, Feb 26 2017 *)
PROG
(PARI) x='x+O('x^50); Vec((-15047*x^2+29600*x-14561)/(x-1)^3) \\ G. C. Greubel, Feb 26 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Marius Coman, Jun 20 2012
EXTENSIONS
Edited by N. J. A. Sloane, Nov 12 2016
STATUS
approved