A053298 Partial sums of A027964.
1, 8, 34, 107, 281, 654, 1397, 2801, 5353, 9859, 17643, 30869, 53062, 89951, 150833, 250780, 414210, 680665, 1114160, 1818310, 2960806, 4813018, 7814074, 12674542, 20544191, 33283434, 53902532, 87272241, 141273663, 228658744
Offset: 0
References
- A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 189, 194-196.
Links
- G. C. Greubel, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (6,-14,15,-5,-4,4,-1)
Programs
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Magma
m:=25; R
:=PowerSeriesRing(Integers(), m); Coefficients(R!((1+2*x)/((1-x-x^2)*(1-x)^5))); // G. C. Greubel, May 24 2018 -
Mathematica
LinearRecurrence[{6,-14,15,-5,-4,4,-1},{1,8,34,107,281,654,1397},30] (* Harvey P. Dale, May 09 2018 *) CoefficientList[Series[(1+2x)/((1-x-x^2)(1-x)^5), {x,0,50}], x] (* G. C. Greubel, May 24 2018 *)
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PARI
x='x+O('x^30); Vec((1+2*x)/((1-x-x^2)*(1-x)^5)) \\ G. C. Greubel, May 24 2018
Formula
a(n) = 3*F(n+10) + F(n+9) - (3*n^4 + 58*n^3 + 489*n^2 + 2234*n + 4752)/24, where F(.) are the Fibonacci numbers (A000045).
a(n) = a(n-1) + a(n-2) + (3*n+4)*C(n+3, 3)/4.
G.f.: (1 + 2*x)/((1 - x - x^2)*(1 - x)^5). - R. J. Mathar, Nov 28 2008