OFFSET
2,1
LINKS
Colin Barker, Table of n, a(n) for n = 2..1000
D. Bochicchio and R. Ferrando, Size-Dependent Transition to High-Symmetry Chiral Structures in AgCu, AgCo, AgNi, and AuNi Nanoalloys, Nano Letters, Vol. 10, No. 10 (2010), 4211-4216.
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
a(n) = 10/3*n^3 + 25*n^2 + 161/3*n + 45 with offset 0.
From Colin Barker, Oct 01 2016: (Start)
a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4) for n>5.
a(n) = 11-(19*n)/3+5*n^2+(10*n^3)/3.
G.f.: x^2*(45-53*x+41*x^2-13*x^3) / (1-x)^4.
(End)
MAPLE
MATHEMATICA
DeleteCases[CoefficientList[Series[x^2*(45 - 53 x + 41 x^2 - 13 x^3)/(1 - x)^4, {x, 0, 39}], x], 0] (* Michael De Vlieger, Oct 02 2016 *)
PROG
(PARI) a(n) = (2*n+1) * (5*n^2+5*n+3) / 3 - 10*(n-1)
(PARI) Vec(x^2*(45-53*x+41*x^2-13*x^3)/(1-x)^4 + O(x^50)) \\ Colin Barker, Oct 01 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Felix Fröhlich, Oct 01 2016
STATUS
approved