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A107248
a(n) = 4*a(n-2) - 4*a(n-4) + 25*a(n-6).
8
1, 1, 1, 37, 37, 169, 169, 553, 553, 2461, 2461, 11857, 11857, 51409, 51409, 219733, 219733, 969721, 969721, 4285177, 4285177, 18755149, 18755149, 82122913, 82122913, 360600481, 360600481, 1582788997, 1582788997, 6941826889
OFFSET
0,4
FORMULA
From R. J. Mathar, Jul 03 2009: (Start)
a(n) = 4*a(n-2) - 4*a(n-4) + 25*a(n-6).
G.f.: -(1+x-3*x^2+33*x^3+37*x^4+25*x^5)/((5*x^3-2*x^2+1)*(5*x^3+2*x^2-1)).
(End)
MATHEMATICA
CoefficientList[Series[-(1 + x - 3 x^2 + 33 x^3 + 37 x^4 + 25 x^5)/((5 x^3 - 2 x^2 + 1) (5 x^3 + 2 x^2 - 1)), {x, 0, 29}], x] (* Michael De Vlieger, Feb 20 2018 *)
LinearRecurrence[{0, 4, 0, -4, 0, 25}, {1, 1, 1, 37, 37, 169}, 30] (* Vincenzo Librandi, Feb 21 2018 *)
PROG
(Magma) I:=[1, 1, 1, 37, 37, 169]; [n le 6 select I[n] else 4*Self(n-2)-4*Self(n-4)+25*Self(n-6): n in [1..40]]; // Vincenzo Librandi, Feb 21 2018
CROSSREFS
Cf. A007493.
Sequence in context: A291478 A257810 A090179 * A219402 A219450 A165858
KEYWORD
nonn,easy,less
AUTHOR
Roger L. Bagula, Jun 08 2005
EXTENSIONS
Edited by N. J. A. Sloane, May 13 2006
New name using Mathar's recurrence from Joerg Arndt, Feb 20 2018
STATUS
approved