The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A109731 a(n) = - 4*a(n-2) - a(n-4), a(0) = 1, a(1) = -4, a(2) = -6, a(3) = 15. 0

%I

%S 1,-4,-6,15,23,-56,-86,209,321,-780,-1198,2911,4471,-10864,-16686,

%T 40545,62273,-151316,-232406,564719,867351,-2107560,-3236998,7865521,

%U 12080641,-29354524,-45085566,109552575,168261623,-408855776

%N a(n) = - 4*a(n-2) - a(n-4), a(0) = 1, a(1) = -4, a(2) = -6, a(3) = 15.

%C Sequence A002530 and A002531 are also generated by the floretion given in the program code.

%H Robert Munafo, <a href="http://www.mrob.com/pub/math/seq-floretion.html">Sequences Related to Floretions</a>

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0, -4, 0, -1).

%F a(2n) = ((-1)^n)*A054491(n), a(2n+1) = ((-1)^n+1)*A001353(n+1). G.f. (1-4*x-2*x^2-x^3)/(x^4+4*x^2+1)

%p Floretion Algebra Multiplication Program, FAMP Code: 1lestesseq[A*B] with A = + .25'i + .25i' + 'ij' + .25'jk' + .25'kj' and B = + j' + k' + 'ii'.

%t LinearRecurrence[{0,-4,0,-1},{1,-4,-6,15},40] (* _Harvey P. Dale_, Mar 05 2013 *)

%Y Cf. A054491, A001353, A002530.

%K easy,sign

%O 0,2

%A _Creighton Dement_, Aug 09 2005

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 25 11:27 EDT 2020. Contains 334592 sequences. (Running on oeis4.)