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A126942
The sequence c[n] defined in A126939.
2
0, 2, 4, 12, 42, 130, 404, 1282, 4044, 12726, 40114, 126450, 398478, 1255796, 3957784, 12473128, 39309510, 123885908, 390432440, 1230465890, 3877871274, 12221294900, 38515986858, 121384948432, 382550391954, 1205625604758, 3799585957042, 11974574363290
OFFSET
0,2
COMMENTS
Linear recurrence and empirical g.f confirmed for more terms. - Ray Chandler, Mar 07 2024
FORMULA
Empirical g.f.: -2*x*(x^2+1) / (x^6+3*x^5+3*x^4+7*x^3+x^2+2*x-1). - Colin Barker, Apr 08 2013
MATHEMATICA
a[0] = 0; a[1] = 2; a[2] = 4; a[3] = 12; a[4] = 42; a[5] = 130; a[n_] := a[n] = a[n-6] + 3*a[n-5] + 3*a[n-4] + 7*a[n-3] + a[n-2] + 2*a[n-1]; Table[a[n], {n, 0, 27}] (* Jean-François Alcover, Nov 23 2016 *)
LinearRecurrence[{2, 1, 7, 3, 3, 1}, {0, 2, 4, 12, 42, 130}, 28] (* or *)
CoefficientList[ Series[-2x*(x^2 + 1)/(x^6 + 3x^5 + 3x^4 + 7x^3 + x^2 + 2x - 1), {x, 0, 27}], x] (* Robert G. Wilson v, Nov 23 2016 *)
CROSSREFS
Sequence in context: A090959 A244035 A340025 * A126947 A188494 A202668
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Mar 18 2007
STATUS
approved