OFFSET
0,5
LINKS
Michael D. Hirschhorn, Non-trivial intertwined second-order recurrence relations, Fibonacci Quart. 43 (2005), no. 4, 316-325. See J_n.
Index entries for linear recurrences with constant coefficients, signature (-1,-2,-2,-1).
FORMULA
a(n) = - a(n-1) - 2*a(n-2) - 2*a(n-3) - a(n-4), n > 3. - Iain Fox, Dec 25 2017
MATHEMATICA
CoefficientList[Series[1/(1+x+2x^2+2x^3+x^4), {x, 0, 60}], x] (* or *) LinearRecurrence[ {-1, -2, -2, -1}, {1, -1, -1, 1}, 60] (* Harvey P. Dale, Nov 19 2020 *)
PROG
(PARI) first(n) = Vec(1/(1 + x + 2*x^2 + 2*x^3 + x^4) + O(x^n)) \\ Iain Fox, Dec 25 2017
CROSSREFS
KEYWORD
sign,easy
AUTHOR
N. J. A. Sloane, Nov 09 2011
STATUS
approved