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A126942 The sequence c[n] defined in A126939. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..27.

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-Fran├žois 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: A264760 A090959 A244035 * A126947 A188494 A202668

Adjacent sequences:  A126939 A126940 A126941 * A126943 A126944 A126945

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mar 18 2007

STATUS

approved

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Last modified November 22 16:26 EST 2019. Contains 329396 sequences. (Running on oeis4.)