A199744 G.f.: 1/(1 + x + 2*x^2 + 2*x^3 + x^4).

1, -1, -1, 1, 2, -1, -4, 1, 7, 0, -12, -3, 20, 10, -32, -25, 49, 55, -71, -112, 95, 216, -111, -399, 94, 710, 11, -1220, -316, 2024, 1037, -3233, -2573, 4941, 5634, -7137, -11440, 9505, 22015, -11008, -40592, 9073, 72112, 1934, -123712, -33453, 204897, 107499, -326675, -264664, 498119, 577060

Offset

0,5

Links

Table of n, a(n) for n=0..51.

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

Sequence in context: A108952 A088522 A252751 * A360870 A115124 A115122

Adjacent sequences: A199741 A199742 A199743 * A199745 A199746 A199747

Keyword

sign,easy

Author

N. J. A. Sloane, Nov 09 2011

Status

approved