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Partial sums of A027941(n-1) with a(-1) = 0.
7

%I #52 Sep 08 2022 08:45:01

%S 0,0,1,5,17,50,138,370,979,2575,6755,17700,46356,121380,317797,832025,

%T 2178293,5702870,14930334,39088150,102334135,267914275,701408711,

%U 1836311880,4807526952,12586269000,32951280073,86267571245,225851433689,591286729850

%N Partial sums of A027941(n-1) with a(-1) = 0.

%H Colin Barker, <a href="/A054452/b054452.txt">Table of n, a(n) for n = 0..1000</a>

%H László Németh, <a href="https://arxiv.org/abs/1701.06022">Pascal pyramid in the space H^2 x R</a>, arXiv:1701.06022 [math.CO], 2017 (5th line of Table 1 is a(n-2)).

%H A. Shriki and O. Liba, <a href="http://www.fq.math.ca/Problems/ElemProbSolnMay16No53.pdf">Polygons with Fibonacci Number Coordinates: Problem B-1167</a>, Fib. Quart. 54,2 May 2016, p. 180-181.

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (5,-8,5,-1).

%F a(n) = +5*a(n-1) -8*a(n-2) +5*a(n-3) -1*a(n-4).

%F G.f.: x^2/((1-x)^2*(1-3*x+x^2)).

%F a(n) = Sum_{k=0..n} A027941(k-1) = F(2*n)-n = A054450(2*n-1, 2) = A054451(2*n-3).

%F G.f.: x^2*Fibe(x)/(1-x)^2, with Fibe(x) := 1/(1-3*x+x^2) = g.f. A001906(n+1) (Fibonacci numbers F(2(n+1))).

%F Fourth diagonal of array defined by T(i, 1) = T(1, j) = 1, T(i, j) = Max(T(i-1, j) + T(i-1, j-1); T(i-1, j-1) + T(i, j-1)). - _Benoit Cloitre_, Aug 05 2003

%F a(n) = Sum_{k=0..n-2} binomial(2*n-k-1, k). - _Johannes W. Meijer_, Aug 12 2013

%F a(n) = Sum_{i=1..n-1} Sum_{j=1..n-1} binomial(i+j, i-j). - _Wesley Ivan Hurt_, Mar 25 2015

%F a(n) = Sum_{k=0..n} (binomial(n+1,k+2)*Fibonacci(k)). - _Vladimir Kruchinin_, Oct 21 2016

%F a(n) = (-((3-sqrt(5))/2)^n + ((3+sqrt(5))/2)^n)/sqrt(5) - n. - _Colin Barker_, Jan 28 2017

%p a[0]:=0: a[1]:=1: for n from 2 to 50 do a[n] := 3*a[n-1]-a[n-2] od: seq(a[n]-n, n=0..27); # _Zerinvary Lajos_, Mar 20 2008

%p with(combinat): seq(fibonacci(2*n)-n, n=0..27); # _Zerinvary Lajos_, Jun 19 2008

%p g:=z/(1-3*z+z^2): gser:=series(g, z=0, 43): seq(abs(coeff(gser, z, n)-n), n=0..27); # _Zerinvary Lajos_, Mar 22 2009

%t CoefficientList[Series[x^2 / ((1 - x)^2 (1 - 3 x + x^2)), {x, 0, 33}], x] (* _Vincenzo Librandi_, Mar 26 2015 *)

%o (Sage) [(lucas_number1(n, 3, 1)-lucas_number1(n, 2, 1)) for n in range(1, 28)]# _Zerinvary Lajos_, Mar 13 2009

%o (Magma) I:=[0,0,1,5]; [n le 4 select I[n] else 5*Self(n-1)-8*Self(n-2)+5*Self(n-3)-Self(n-4): n in [1..30]]; // _Vincenzo Librandi_, Mar 26 2015

%o (Maxima)

%o makelist(sum(fib(k)*binomial(n+1,k+2),k,0,n),n,0,20); /* _Vladimir Kruchinin_, Oct 21 2016 */

%o (PARI) concat(vector(2), Vec(x^2/((1-x)^2*(1-3*x+x^2)) + O(x^40))) \\ _Colin Barker_, Jan 28 2017

%Y Cf. A027941, A054451, A001906, A052952.

%K easy,nonn

%O 0,4

%A _Wolfdieter Lang_, Apr 27 2000

%E More terms from _James A. Sellers_, Apr 28 2000

%E a(0) added by _Arkadiusz Wesolowski_, Jun 07 2011