OFFSET
0,4
COMMENTS
This is the inverse binomial transform of A141425 if interpreted with offset 0.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (-6,-15,-20,-15,-6).
FORMULA
G.f.: (1 +7*x +22*x^2 +39*x^3 +42*x^4 +27*x^5)/((1+x+x^2)*(1+3*x+3*x^2)*(1+2*x)). - R. J. Mathar, Nov 11 2008
From G. C. Greubel, Mar 30 2021: (Start)
a(n) = (9/2)*[n=0] + (-2)^(n-1) - (3/2)*( ChebyshevU(n, -1/2) + 2*ChebyshevU(n-1, -1/2) + 3^((n-1)/2)*(sqrt(3)*ChebyshevU(n, -sqrt(3)/2] + 2*ChebyshevU(n-1, -sqrt(3)/2) ).
MATHEMATICA
LinearRecurrence[{-6, -15, -20, -15, -6}, {1, 1, 1, -2, 4, -8}, 40] (* G. C. Greubel, Mar 30 2021 *)
PROG
(Magma) I:=[1, 1, -2, 4, -8]; [1] cat [n le 5 select I[n] else -6*Self(n-1) -15*Self(n-2) -20*Self(n-3) -15*Self(n-4) -6*Self(n-5): n in [1..40]]; // G. C. Greubel, Mar 30 2021
(Sage)
def A141532_list(prec):
P.<x> = PowerSeriesRing(ZZ, prec)
return P( (1 +7*x +22*x^2 +39*x^3 +42*x^4 +27*x^5)/((1+x+x^2)*(1+3*x+3*x^2)*(1+2*x)) ).list()
A141532_list(40) # G. C. Greubel, Mar 30 2021
CROSSREFS
KEYWORD
sign
AUTHOR
Paul Curtz, Aug 12 2008
EXTENSIONS
Extended by R. J. Mathar, Nov 11 2008
STATUS
approved