login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A110225
Expansion of (-1+3*x+2*x^2-8*x^3+3*x^5-2*x^6-2*x^7+x^8) / ((x-1)*(x+1)*(x^2-2*x-1)*(x^2+2*x-1)).
1
1, -3, 5, -13, 28, -73, 164, -421, 956, -2449, 5572, -14269, 32476, -83161, 189284, -484693, 1103228, -2824993, 6430084, -16465261, 37477276, -95966569, 218433572, -559334149, 1273124156, -3260038321, 7420311364, -19000895773, 43248744028, -110745336313
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)
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
Sequence in context: A160823 A077443 A147196 * A065047 A282565 A295617
KEYWORD
easy,sign
AUTHOR
Creighton Dement, Sep 06 2005
STATUS
approved