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A138268
Negative of the Hankel transform of C(n)-C(n+2), where C(n)=A000108(n).
1
1, 4, -17, 17, 72, -305, 305, 1292, -5473, 5473, 23184, -98209, 98209, 416020, -1762289, 1762289, 7465176, -31622993, 31622993, 133957148, -567451585, 567451585, 2403763488, -10182505537, 10182505537
OFFSET
0,2
COMMENTS
-a(n) is the Hankel transform of C(n)-C(n+2).
FORMULA
G.f.: (1+7x+3x^2+x^3)/(1+3x+8x^2+3x^3+x^4); a(n)=(Fibonacci(3*floor((2n+5)/3))/Fibonacci(3))*(4*sin(2*pi*n/3+pi/6)/3+1/3);
a(0)=1, a(1)=4, a(2)=-17, a(3)=17, a(n)=-3*a(n-1)-8*a(n-2)-3*a(n-3)- a(n-4) [From Harvey P. Dale, May 26 2011]
MATHEMATICA
LinearRecurrence[{-3, -8, -3, -1}, {1, 4, -17, 17}, 41] (* or )* CoefficientList[ Series[(1+7x+3x^2+x^3)/(1+3x+8x^2+3x^3+x^4), {x, 0, 40}], x] (* Harvey P. Dale, May 26 2011 *)
CROSSREFS
Cf. A001076.
Sequence in context: A057596 A070712 A195884 * A031444 A031033 A128981
KEYWORD
easy,sign
AUTHOR
Paul Barry, Mar 10 2008
STATUS
approved