OFFSET
0,2
COMMENTS
Floretion Algebra Multiplication Program, FAMP Code: 4baseksigcycsumseq[A*B] with A = + 'i + .5'ii' + .5'jj' + .5'kk' + .5e and B = - .25'j + .25'k - .25j' + .25k' - .5'ii' - .25'ij' - .25'ik' - .25'ji' - .25'ki' - .5e; sumtype: (Y[15], *, sum/2)
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (0,7,0,-7,0,1).
FORMULA
a(n) = -5*A000129(n+1) +12*A000129(n) -1/2 +(-1)^n/2 +(-1)^n*A000129(n+1), if n>2. - R. J. Mathar, Nov 10 2009
a(n) = 7*a(n-2) - 7*a(n-4) + a(n-6) for n>8. - Colin Barker, May 16 2019
PROG
(PARI) Vec((1 - 3*x - 2*x^2 + 8*x^3 - 3*x^5 + 2*x^6 + 2*x^7 - x^8) / ((1 - x)*(1 + x)*(1 + 2*x - x^2)*(1 - 2*x - x^2)) + O(x^30)) \\ Colin Barker, May 16 2019
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Creighton Dement, Sep 06 2005
STATUS
approved