OFFSET
0,4
REFERENCES
Richard Bronson, Schaum's Outline of Modern Introductory Differential Equations, MacGraw-Hill, New York,1973, page 107, solved problem 19.17
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..400
FORMULA
a(n) = n!*b(n), where b(n) = (1 + n - n^2)*b(n-2)/(n*(n-1)) and b(0) = b(1) = 1.
a(n) = (1 + n - n^2)*a(n-2), with a(0) = a(1) = 1. - G. C. Greubel, Jul 20 2021
MATHEMATICA
b[n_]:= b[n]= If[n<2, 1, (1 +n -n^2)*b[n-2]/(n*(n-1))]; Table[b[n]*n!, {n, 0, 30}]
PROG
(Magma)
function a(n)
if n lt 2 then return 1;
else return (1 +n -n^2)*a(n-2);
end if; return a;
end function;
[a(n): n in [0..30]]; // G. C. Greubel, Jul 20 2021
(Sage)
def b(n): return 1 if (n<2) else (1 +n -n^2)*b(n-2)/(n*(n-1))
def a(n): return factorial(n)*b(n)
[a(n) for n in (0..30)] # G. C. Greubel, Jul 20 2021
CROSSREFS
KEYWORD
sign
AUTHOR
Roger L. Bagula, Sep 24 2006
EXTENSIONS
Edited by N. J. A. Sloane, Jan 06 2009
Edited by G. C. Greubel, Jul 20 2021
STATUS
approved