OFFSET
1,1
COMMENTS
Most quintic polynomials x^5 + 5x(5*n^2+20n+4) + 8(5*n^2+20n+4) (with the exception of n=0 or 4 when the polynomial is solvable, or n=-2 when it is reducible) have nonsolvable alternating Galois group A_5 (of order 60) over rational numbers.
LINKS
Index entries for linear recurrences with constant coefficients, signature (3, -3, 1).
FORMULA
G.f.: -x*(29-23*x+4*x^2)/(-1+x)^3. - R. J. Mathar, Nov 14 2007
MATHEMATICA
Table[5n^2 + 20n + 4, {n, 1, 30}]
PROG
(PARI) a(n)=5*n^2+20*n+4 \\ Charles R Greathouse IV, Jun 17 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Artur Jasinski, Oct 31 2007, Nov 21 2007
STATUS
approved