OFFSET
2,1
REFERENCES
Appeared in University of Texas Interscholastic League High School Number Sense District Test, 2004.
LINKS
G. C. Greubel, Table of n, a(n) for n = 2..445
Index entries for linear recurrences with constant coefficients, signature (2,0,-2,1).
FORMULA
Conjecture: a(n) +(-n-3)*a(n-1) +(2*n+1)*a(n-2) +(-n+1)*a(n-3)=0. - R. J. Mathar, Sep 27 2014
a(n) = 3 - (n+1)!. - Michel Marcus, Jun 07 2020
From G. C. Greubel, Jun 07 2020: (Start)
E.g.f.: 3*exp(x) - (3 - 3*x + x^3)/(1-x)^2. (End)
MAPLE
MATHEMATICA
Table[i; 1 - Sum[n n!, {n, 2, i}], {i, 2, 20}]
PROG
(PARI) a(n) = 1 - sum(k=2, n, k*k!); \\ Michel Marcus, Jun 07 2020
(Sage) [3-factorial(n+1) for n in (2..20)] # G. C. Greubel, Jun 07 2020
CROSSREFS
KEYWORD
sign
AUTHOR
Doug Ray (draymath(AT)iastate.edu), Apr 11 2004
STATUS
approved