OFFSET
0,6
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,3,-3,-3,3,1,-1).
FORMULA
a(n) = n*(n-1)*(n-3)/8 when n odd; n*(n-2)*(n-4)/8 when n even.
G.f.: x^5*(x+5)/((1-x)(1-x^2)^3). - Michael Somos, Jan 30 2004
For n odd, a(n) = A080838(n). - Gerald McGarvey, Sep 14 2008
a(n) = n*(2*n-3-(-1)^n)*(2*n-7-(-1)^n)/32. - Wesley Ivan Hurt, Dec 31 2013
E.g.f.: x*((x - 3)*x*cosh(x) + (x^2 - x + 3)*sinh(x))/8. - Stefano Spezia, May 28 2022
MAPLE
A060423:=n->n*(2*n-3-(-1)^n)*(2*n-7-(-1)^n)/32; seq(A060423(n), n=0..100); # Wesley Ivan Hurt, Dec 31 2013
MATHEMATICA
Table[n(2n-3-(-1)^n)(2n-7-(-1)^n)/32, {n, 0, 100}] (* Wesley Ivan Hurt, Dec 31 2013 *)
Table[If[EvenQ[n], (n(n-2)(n-4))/8, (n(n-1)(n-3))/8], {n, 0, 50}] (* Harvey P. Dale, Sep 18 2018 *)
PROG
(PARI) a(n)=polcoeff(x^5*(5+x)/(1-x)/(1-x^2)^3+x*O(x^n), n)
(Magma) [n*(2*n-3-(-1)^n)*(2*n-7-(-1)^n)/32 : n in [0..60]]; // Wesley Ivan Hurt, Apr 14 2017
CROSSREFS
KEYWORD
easy,nice,nonn
AUTHOR
Sen-Peng Eu, Apr 05 2001
STATUS
approved