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”).

A158501
Hankel transform of A158500.
2
1, 0, 25, -24, 105, -104, 273, -272, 561, -560, 1001, -1000, 1625, -1624, 2465, -2464, 3553, -3552, 4921, -4920, 6601, -6600, 8625, -8624, 11025, -11024, 13833, -13832, 17081, -17080, 20801, -20800, 25025, -25024, 29785, -29784, 35113, -35112, 41041, -41040
OFFSET
0,3
FORMULA
G.f.: (1+x+22*x^2-2*x^3+9*x^4+x^5) / ((1-x)^3*(1+x)^4).
a(n) = -a(n-1)+3*a(n-2)+3*a(n-3)-3*a(n-4)-3*a(n-5)+a(n-6)+a(n-7).
From Colin Barker, Jan 29 2016: (Start)
a(n) = (n+1)*(2*(-1)^n*n^2+4*(-1)^n*n+3*n+3)/3.
a(n) = (2*n^3+9*n^2+10*n+3)/3 for n even.
a(n) = (-2*n^3-3*n^2+2*n+3)/3 for n odd.
(End)
MATHEMATICA
LinearRecurrence[{-1, 3, 3, -3, -3, 1, 1}, {1, 0, 25, -24, 105, -104, 273}, 40] (* Harvey P. Dale, Aug 19 2012 *)
PROG
(PARI) Vec((1+x+22*x^2-2*x^3+9*x^4+x^5)/((1-x)^3*(1+x)^4) + O(x^50)) \\ Colin Barker, Jan 29 2016
CROSSREFS
Sequence in context: A061438 A022981 A023467 * A330272 A194219 A291434
KEYWORD
easy,sign
AUTHOR
Paul Barry, Mar 20 2009
STATUS
approved