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A027974 a(n) = Sum_{i=0..n} Sum_{j=0..i} T(i,j), T given by A027960. 7
1, 5, 14, 35, 81, 180, 389, 825, 1726, 3575, 7349, 15020, 30561, 61965, 125294, 252795, 509161, 1024100, 2057549, 4130225, 8284926, 16609455, 33282989, 66669660, 133507081, 267285605, 535010414, 1070731475, 2142612801 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (3,-1,-2).

FORMULA

a(n) = 8*2^n - Fibonacci(n+5) - Fibonacci(n+3).

a(n) = A101220(4, 2, n+1).

G.f.: (1+2*x)/((1-2*x)*(1-x-x^2)). - R. J. Mathar, Sep 22 2008

MAPLE

with(combinat); f:=fibonacci; seq(2^(n+3) - f(n+5) - f(n+3), n=0..30); # G. C. Greubel, Sep 26 2019

MATHEMATICA

Table[2^(n+3) - LucasL[n+4], {n, 0, 30}] (* G. C. Greubel, Sep 26 2019 *)

PROG

(PARI) vector(31, n, f=fibonacci; 2^(n+2) - f(n+4) - f(n+2)) \\ G. C. Greubel, Sep 26 2019

(MAGMA) [2^(n+3) - Lucas(n+4): n in [0..30]]; // G. C. Greubel, Sep 26 2019

(Sage) [2^(n+3) - lucas_number2(n+4, 1, -1) for n in (0..30)] # G. C. Greubel, Sep 26 2019

(GAP) List([0..30], n-> 2^(n+3) - Lucas(1, -1, n+4)[2]); # G. C. Greubel, Sep 26 2019

CROSSREFS

Cf. A000032, A000045, A027960.

Sequence in context: A001215 A066767 A227200 * A027983 A142585 A234097

Adjacent sequences:  A027971 A027972 A027973 * A027975 A027976 A027977

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified October 21 03:24 EDT 2019. Contains 328291 sequences. (Running on oeis4.)