OFFSET
0,4
COMMENTS
First differences are (-1)^n*A022998(n).
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (1,2,-2,-1,1).
FORMULA
MATHEMATICA
LinearRecurrence[{1, 2, -2, -1, 1}, {0, 0, -1, 3, 0}, 60] (* Harvey P. Dale, Jun 01 2015 *)
PROG
(Magma) [(2*n^2-2*n-3)/8+3*(-1)^n*(1-2*n)/8: n in [0..60]]; // Vincenzo Librandi, Aug 04 2011
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Paul Curtz, Nov 28 2010
STATUS
approved