A106852 -id:A106852 - cp's OEIS frontend

A177694 Triangle t(n,m) = p(n)/ (p(m)*p(n-m) ) read by rows, where p(n>=1) = 1, -1, 2, 10, 10, -160, -2080,.. are partial products of A106852.

1, 1, 1, 1, -1, 1, 1, -2, -2, 1, 1, 5, 10, 5, 1, 1, 1, -5, -5, 1, 1, 1, -16, 16, -40, 16, -16, 1, 1, 13, 208, -104, -104, 208, 13, 1, 1, 35, -455, -3640, -728, -3640, -455, 35, 1, 1, -74, 2590, -16835, 53872, 53872, -16835, 2590, -74, 1, 1, -31, -2294, 40145, 104377

Offset: 0

Roger L. Bagula, May 11 2010

Row sums are: 1, 2, 1, -2, 22, -6, -38, 236, -8846, 79108, -1385636,...

			1;
1, 1;
1, -1, 1;
1, -2, -2, 1;
1, 5, 10, 5, 1;
1, 1, -5, -5, 1, 1;
1, -16, 16, -40, 16, -16, 1;
1, 13, 208, -104, -104, 208, 13, 1;
1, 35, -455, -3640, -728, -3640, -455, 35, 1;
1, -74, 2590, -16835, 53872, 53872, -16835, 2590, -74, 1;
1, -31, -2294, 40145, 104377, -1670032, 104377, 40145, -2294, -31, 1;

Advanced Number Theory, Harvey Cohn, Dover Books,1963, Page 47ff

Clear[t, n, m, c, q, w, f, a];
f[0, a_] := 0; f[1, a_] := 1;
f[n_, a_] := f[n, a] = -f[n - 1, a] - a*f[n - 2, a];
c[n_, a_] := If[n == 0, 1, Product[f[i, a], {i, 1, n}]];
w[n_, m_, q_] := c[n, q]/(c[m, q]*c[n - m, q]);
Table[Flatten[Table[Table[w[n, m, q], {m, 0, n}], {n, 0, 10}]], {q, 2, 12}]

p(n+1) = product_{i=0..n} (-1)^i*A106852(i).

t(n,m) = p(n)/(p(m)*p(n-m)).

A109466 Riordan array (1, x(1-x)).

Original entry on oeis.org

1, 0, 1, 0, -1, 1, 0, 0, -2, 1, 0, 0, 1, -3, 1, 0, 0, 0, 3, -4, 1, 0, 0, 0, -1, 6, -5, 1, 0, 0, 0, 0, -4, 10, -6, 1, 0, 0, 0, 0, 1, -10, 15, -7, 1, 0, 0, 0, 0, 0, 5, -20, 21, -8, 1, 0, 0, 0, 0, 0, -1, 15, -35, 28, -9, 1, 0, 0, 0, 0, 0, 0, -6, 35, -56, 36, -10, 1, 0, 0, 0, 0, 0, 0, 1, -21, 70, -84, 45, -11, 1, 0, 0, 0, 0

Offset: 0

Philippe Deléham, Aug 28 2005

Inverse is Riordan array (1, xc(x)) (A106566).
Triangle T(n,k), 0 <= k <= n, read by rows, given by [0, -1, 1, 0, 0, 0, 0, 0, 0, ...] DELTA [1, 0, 0, 0, 0, 0, 0, 0, ...] where DELTA is the operator defined in A084938.
Modulo 2, this sequence gives A106344. - Philippe Deléham, Dec 18 2008
Coefficient array of the polynomials Chebyshev_U(n, sqrt(x)/2)*(sqrt(x))^n. - Paul Barry, Sep 28 2009

			Rows begin:
  1;
  0,  1;
  0, -1,  1;
  0,  0, -2,  1;
  0,  0,  1, -3,  1;
  0,  0,  0,  3, -4,   1;
  0,  0,  0, -1,  6,  -5,   1;
  0,  0,  0,  0, -4,  10,  -6,   1;
  0,  0,  0,  0,  1, -10,  15,  -7,  1;
  0,  0,  0,  0,  0,   5, -20,  21, -8,  1;
  0,  0,  0,  0,  0,  -1,  15, -35, 28, -9, 1;
From _Paul Barry_, Sep 28 2009: (Start)
Production array is
  0,    1,
  0,   -1,    1,
  0,   -1,   -1,   1,
  0,   -2,   -1,  -1,   1,
  0,   -5,   -2,  -1,  -1,  1,
  0,  -14,   -5,  -2,  -1, -1,  1,
  0,  -42,  -14,  -5,  -2, -1, -1,  1,
  0, -132,  -42, -14,  -5, -2, -1, -1,  1,
  0, -429, -132, -42, -14, -5, -2, -1, -1, 1 (End)

Paul Barry, Embedding structures associated with Riordan arrays and moment matrices, arXiv preprint arXiv:1312.0583 [math.CO], 2013.
Tom Copeland, Addendum to Elliptic Lie Triad

Cf. A026729 (unsigned version), A000108, A030528, A124644.

/* As triangle */ [[(-1)^(n-k)*Binomial(k, n-k): k in [0..n]]: n in [0.. 15]]; // Vincenzo Librandi, Jan 14 2016

(* The function RiordanArray is defined in A256893. *)
RiordanArray[1&, #(1-#)&, 13] // Flatten (* Jean-François Alcover, Jul 16 2019 *)

Number triangle T(n, k) = (-1)^(n-k)*binomial(k, n-k).
T(n, k)*2^(n-k) = A110509(n, k); T(n, k)*3^(n-k) = A110517(n, k).
Sum_{k=0..n} T(n,k)*A000108(k)=1. - Philippe Deléham, Jun 11 2007
From Philippe Deléham, Oct 30 2008: (Start)
Sum_{k=0..n} T(n,k)*A144706(k) = A082505(n+1).
Sum_{k=0..n} T(n,k)*A002450(k) = A100335(n).
Sum_{k=0..n} T(n,k)*A001906(k) = A100334(n).
Sum_{k=0..n} T(n,k)*A015565(k) = A099322(n).
Sum_{k=0..n} T(n,k)*A003462(k) = A106233(n). (End)
Sum_{k=0..n} T(n,k)*x^(n-k) = A053404(n), A015447(n), A015446(n), A015445(n), A015443(n), A015442(n), A015441(n), A015440(n), A006131(n), A006130(n), A001045(n+1), A000045(n+1), A000012(n), A010892(n), A107920(n+1), A106852(n), A106853(n), A106854(n), A145934(n), A145976(n), A145978(n), A146078(n), A146080(n), A146083(n), A146084(n) for x = -12,-11,-10,-9,-8,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10,11,12 respectively. - Philippe Deléham, Oct 27 2008
Sum_{k=0..n} T(n,k)*x^k = A000007(n), A010892(n), A099087(n), A057083(n), A001787(n+1), A030191(n), A030192(n), A030240(n), A057084(n), A057085(n+1), A057086(n) for x = 0,1,2,3,4,5,6,7,8,9,10 respectively. - Philippe Deléham, Oct 28 2008
G.f.: 1/(1-y*x+y*x^2). - Philippe Deléham, Dec 15 2011
T(n,k) = T(n-1,k-1) - T(n-2,k-1), T(n,0) = 0^n. - Philippe Deléham, Feb 15 2012
Sum_{k=0..n} T(n,k)*x^(n-k) = F(n+1,-x) where F(n,x)is the n-th Fibonacci polynomial in x defined in A011973. - Philippe Deléham, Feb 22 2013
Sum_{k=0..n} T(n,k)^2 = A051286(n). - Philippe Deléham, Feb 26 2013
Sum_{k=0..n} T(n,k)*T(n+1,k) = -A110320(n). - Philippe Deléham, Feb 26 2013
For T(0,0) = 0, the signed triangle below has the o.g.f. G(x,t) = [t*x(1-x)]/[1-t*x(1-x)] = L[t*Cinv(x)] where L(x) = x/(1-x) and Cinv(x)=x(1-x) with the inverses Linv(x) = x/(1+x) and C(x)= [1-sqrt(1-4*x)]/2, an o.g.f. for the shifted Catalan numbers A000108, so the inverse o.g.f. is Ginv(x,t) = C[Linv(x)/t] = [1-sqrt[1-4*x/(t(1+x))]]/2 (cf. A124644 and A030528). - Tom Copeland, Jan 19 2016

A190958 a(n) = 2a(n-1) - 10a(n-2), with a(0) = 0, a(1) = 1.

Original entry on oeis.org

0, 1, 2, -6, -32, -4, 312, 664, -1792, -10224, -2528, 97184, 219648, -532544, -3261568, -1197696, 30220288, 72417536, -157367808, -1038910976, -504143872, 9380822016, 23803082752, -46202054656, -330434936832, -198849327104, 2906650714112, 7801794699264

Offset: 0

Vladimir Joseph Stephan Orlovsky, May 24 2011

For the difference equation a(n) = c*a(n-1) - d*a(n-2), with a(0) = 0, a(1) = 1, the solution is a(n) = d^((n-1)/2) * ChebyshevU(n-1, c/(2*sqrt(d))) and has the alternate form a(n) = ( ((c + sqrt(c^2 - 4*d))/2)^n - ((c - sqrt(c^2 - 4*d))/2)^n )/sqrt(c^2 - 4*d). In the case c^2 = 4*d then the solution is a(n) = n*d^((n-1)/2). The generating function is x/(1 - c*x + d^2) and the exponential generating function takes the form (2/sqrt(c^2 - 4*d))*exp(c*x/2)*sinh(sqrt(c^2 - 4*d)*x/2) for c^2 > 4*d, (2/sqrt(4*d - c^2))*exp(c*x/2)*sin(sqrt(4*d - c^2)*x/2) for 4*d > c^2, and x*exp(sqrt(d)*x) if c^2 = 4*d. - G. C. Greubel, Jun 10 2022

Vincenzo Librandi, Table of n, a(n) for n = 0..190
Index entries for linear recurrences with constant coefficients, signature (2,-10).

Sequences of the form a(n) = c*a(n-1) - d*a(n-2), with a(0)=0, a(1)=1:
c/d...1.......2.......3.......4.......5.......6.......7.......8.......9......10
.A128834,A107920,A106852,A106853,A106854,A145934,A145976,A145978,A146078,A146080
.A000027,A009545,A088137,A088138,A045873,A088139,A089181,A090591,A127357,A190958
.A001906,A000225,A057083,A049072,A190959,A190960,A190961,A190962,A190963,A190964
.A001353,A007070,A003462,A001787,A099456,A190965,A168175,A190966,A190967,A190968
.A004254,A107839,A116415,A002450,A030191,A001047,A099450,A190969,A190970,A190971
.A001109,A154244,A138395,A084326,A003463,A030192,A081179,A006516,A027471,A106392
.A004187,A186446,A190972,A190973,A190974,A003464,A030240,A152268,A099459,A016127
.A001090,A190975,A190976,A099156,A190977,A190978,A023000,A057084,A154245,A154235
.A018913,A190979,A190980,A190981,A190982,A190983,A190984,A023001,A057085,A178869
A004189,A190869,A190985,A190986,A190987,A190988,A190989,A190990,A002452,A057086

I:=[0,1]; [n le 2 select I[n] else 2*Self(n-1)-10*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Sep 17 2011

Mathematica
```
LinearRecurrence[{2,-10}, {0,1}, 50]
```

a(n)=([0,1; -10,2]^n*[0;1])[1,1] \\ Charles R Greathouse IV, Apr 08 2016

[lucas_number1(n,2,10) for n in (0..50)] # G. C. Greubel, Jun 10 2022

G.f.: x / ( 1 - 2*x + 10*x^2 ). - R. J. Mathar, Jun 01 2011
E.g.f.: (1/3)*exp(x)*sin(3*x). - Franck Maminirina Ramaharo, Nov 13 2018
a(n) = 10^((n-1)/2) * ChebyshevU(n-1, 1/sqrt(10)). - G. C. Greubel, Jun 10 2022
a(n) = (1/3)*10^(n/2)*sin(n*arctan(3)) = Sum_{k=0..floor(n/2)} (-1)^k*3^(2*k)*binomial(n,2*k+1). - Gerry Martens, Oct 15 2022

A106853 Expansion of 1/(1 - x + 4*x^2).

Original entry on oeis.org

1, 1, -3, -7, 5, 33, 13, -119, -171, 305, 989, -231, -4187, -3263, 13485, 26537, -27403, -133551, -23939, 510265, 606021, -1435039, -3859123, 1881033, 17317525, 9793393, -59476707, -98650279, 139256549, 533857665, -23168531, -2158599191, -2065925067

Offset: 0

Paul Barry, May 08 2005

Row sums of Riordan array (1,x(1-4x)). In general, a(n) = Sum_{k=0..n} (-1)^(n-k)*binomial(k,n-k)*r^(n-k) yields the row sums of the Riordan array (1,x(1-kx)).
For n >= 1, a(n) equals the determinant of the n X n matrix with 2's along the superdiagonal and the subdiagonal, and 1's along the main diagonal, and 0's everywhere else. - John M. Campbell, Jun 04 2011
For n >= 1, |a(n-1)| is the unique odd positive solution x to 4^(n+1) = 15*x^2 + y^2. The value of y is |A272931(n)|. - Jianing Song, Jan 22 2019
Define the sequence u(n) = (u(n-1) + u(n-2))/u(n-3) with u(1) = 1, u(2) = -1, u(3) = 2. Then u(4*n) = 2*(a(n-1)+4*a(n-2))*a(n-1)/(a(n)+a(n-1))/a(n), u(4*n+1) = a(n+1)/a(n), u(4*n+2) = -1, u(4*n+3) = 4*(a(n)+a(n-1))/(a(n)+a(n+1)). For example, a(2) = -3, a(3) = -7 and u(8) = 5/3, u(9) = 7/3, u(10) = -1. - Michael Somos, Oct 24 2023

			G.f. = 1 + x - 3*x^2 - 7*x^3 + 5*x^4 + 33*x^5 + 13*x^6 - 119*x^7 - 171*x^8 + ... - _Michael Somos_, Oct 24 2023

T. D. Noe, Table of n, a(n) for n = 0..1000
Paul Barry, On a Central Transform of Integer Sequences, arXiv:2004.04577 [math.CO], 2020.
Taras Goy and Mark Shattuck, Determinants of Toeplitz-Hessenberg Matrices with Generalized Leonardo Number Entries, Ann. Math. Silesianae (2023). See p. 15.
Index entries for linear recurrences with constant coefficients, signature (1,-4).

Cf. A106852, A272931.

I:=[1,1]; [n le 2 select I[n] else Self(n-1) - 4*Self(n-2): n in [1..30]]; // G. C. Greubel, Jan 14 2018

f:= gfun:-rectoproc({a(n)=a(n-1)-4*a(n-2), a(0)=1,a(1)=1},a(n),remember):
map(f, [$0..100]); # Robert Israel, Jan 15 2018

Join[{a=1,b=1},Table[c=b-4*a;a=b;b=c,{n,80}]] (* Vladimir Joseph Stephan Orlovsky, Jan 22 2011 *)
CoefficientList[Series[1/(1-x*(1-4x)),{x,0,40}],x] (* or *) LinearRecurrence[ {1,-4},{1,1},40] (* Harvey P. Dale, May 26 2013 *)
a[ n_] := 2^n * ChebyshevU[n, 1/4]; (* Michael Somos, Oct 24 2023 *)

x='x+O('x^30); Vec(1/(1-x+4*x^2)) \\ G. C. Greubel, Jan 14 2018

{a(n) = 2^n*polchebyshev(n, 2, 1/4)}; /* Michael Somos, Oct 24 2023 */

[lucas_number1(n,1,4) for n in range(1, 36)] # Zerinvary Lajos, Apr 22 2009

G.f.: 1/(1 - x + 4*x^2).
a(n) = 2^n*(cos(2*n*arctan(sqrt(15)/5))+sqrt(15)*sin(2*n*arctan(sqrt(15)/5))/15).
a(n) = ((1 + sqrt(-15))^(n+1) - (1 - sqrt(-15))^(n+1))/(2^(n+1)*sqrt(-15)).
a(n) = Sum_{k=0..n} ((-1)^(n-k)*binomial(k, n-k)*4^(n-k)).
a(n) = a(n-1) - 4*a(n-2), a(0) = 1, a(1) = 1. - Philippe Deléham, Oct 21 2008
a(n) = Sum_{k=0..n} A109466(n,k)*4^(n-k). - Philippe Deléham, Oct 25 2008
G.f.: 1/(1 - 2*x)^2/(1 + 3*x*G(0)/2), where G(k) = 1 + 1/(1 - x/(x + (k + 1)/(2*k + 4)/G(k+1))); (continued fraction). - Sergei N. Gladkovskii, Jun 01 2013
For n >= 1, 15*A272931(n)^2 + a(n-1)^2 = 4^(n+1). - Jianing Song, Jan 22 2019
a(n) = Product_{k=1..n} (1 + 4*cos(k*Pi/(n+1))). - Peter Luschny, Nov 28 2019
a(n) = 2^n * U(n, 1/4), where U(n, x) is the Chebyshev polynomial of the second kind. - Federico Provvedi, Mar 28 2022

A106854 Expansion of 1/(1-x(1-5x)).

Original entry on oeis.org

1, 1, -4, -9, 11, 56, 1, -279, -284, 1111, 2531, -3024, -15679, -559, 77836, 80631, -308549, -711704, 831041, 4389561, 234356, -21713449, -22885229, 85682016, 200108161, -228301919, -1228842724, -87333129, 6056880491, 6493546136, -23790856319, -56258586999, 62695694596, 343988629591

Offset: 0

Paul Barry, May 08 2005

Row sums of Riordan array (1,x*(1-5*x)). In general, a(n) = Sum_{k=0..n}(-1)^(n-k)*binomial(k,n-k)*r^(n-k), yields the row sums of the Riordan array (1,x*(1-k*x)).

Seiichi Manyama, Table of n, a(n) for n = 0..2859
Taras Goy and Mark Shattuck, Determinants of Toeplitz-Hessenberg Matrices with Generalized Leonardo Number Entries, Ann. Math. Silesianae (2023). See p. 16.
Index entries for linear recurrences with constant coefficients, signature (1,-5).

Cf. A106852, A106853, A145934.

I:=[1,1]; [n le 2 select I[n] else Self(n-1) - 5*Self(n-2): n in [1..30]]; // G. C. Greubel, Jan 14 2018

Join[{a=1,b=1},Table[c=b-5*a;a=b;b=c,{n,80}]] (* Vladimir Joseph Stephan Orlovsky, Jan 22 2011 *)
CoefficientList[Series[1/(1-x(1-5x)),{x,0,40}],x] (* or *) LinearRecurrence[ {1,-5},{1,1},40] (* Harvey P. Dale, Jan 21 2012 *)

Vec(1/(1-x+5*x^2) + O(x^99)) \\ Altug Alkan, Sep 06 2016

[lucas_number1(n,1,5) for n in range(1,35)] # Zerinvary Lajos, Jul 16 2008

a(n) = ((1+sqrt(-19))^(n+1)-(1-sqrt(-19))^(n+1))/(2^(n+1)sqrt(-19)).
a(n) = Sum_{k=0..n} (-1)^(n-k)*binomial(k, n-k)*5^(n-k).
a(n) = 5^(n/2)(cos(-n*acot(sqrt(19)/19))-sqrt(19)sin(-n*acot(sqrt(19)/19))/19).
a(n) = a(n-1)-5*a(n-2), a(0)=1, a(1)=1. - Philippe Deléham, Oct 21 2008
a(n) = Sum_{k=0..n} A109466(n,k)*5^(n-k). - Philippe Deléham, Oct 25 2008
G.f.: Q(0)/2, where Q(k) = 1 + 1/( 1 - x*(2*k+1 -5*x)/( x*(2*k+2 -5*x) + 1/Q(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Dec 07 2013

A145934 Expansion of 1/(1-x(1-6x)).

Original entry on oeis.org

1, 1, -5, -11, 19, 85, -29, -539, -365, 2869, 5059, -12155, -42509, 30421, 285475, 102949, -1609901, -2227595, 7431811, 20797381, -23793485, -148577771, -5816861, 885649765, 920550931, -4393347659, -9916653245, 16443432709

Offset: 0

Philippe Deléham, Oct 25 2008

Row sums of Riordan array (1, x(1-6x)).

For positive n, a(n) equals the determinant of the n X n tridiagonal matrix with 1's along the main diagonal, 3's along the superdiagonal, and 2's along the subdiagonal (see Mathematica code below). - John M. Campbell, Jul 08 2011

Seiichi Manyama, Table of n, a(n) for n = 0..2569
Taras Goy and Mark Shattuck, Determinants of Toeplitz-Hessenberg Matrices with Generalized Leonardo Number Entries, Ann. Math. Silesianae (2023). See p. 17.
Index entries for linear recurrences with constant coefficients, signature (1,-6).

Cf. A010892, A107920, A106852, A106853, A106854.

I:=[1,1]; [n le 2 select I[n] else Self(n-1) - 6*Self(n-2): n in [1..30]]; // G. C. Greubel, Jan 14 2018

Table[Det[Array[KroneckerDelta[#1, #2] + KroneckerDelta[#1, #2 + 1]*2 + KroneckerDelta[#1, #2 - 1]*3 &, {n, n}]], {n, 1, 40}] (* John M. Campbell, Jul 08 2011 *)
LinearRecurrence[{1,-6}, {1,1}, 30] (* G. C. Greubel, Jan 14 2018 *)

Vec(1/(1-x*(1-6*x))+O(x^99)) \\ Charles R Greathouse IV, Sep 23 2012

[lucas_number1(n,1,6) for n in range(1, 29)] # Zerinvary Lajos, Apr 22 2009

a(n) = Sum_{k=0..n} A109466(n,k)*6^(n-k).

a(n) = a(n-1) - 6*a(n-2); a(0)=1, a(1)=1. - Philippe Deléham, Oct 25 2008

A145976 Expansion of 1/(1-x(1-7x)).

Original entry on oeis.org

1, 1, -6, -13, 29, 120, -83, -923, -342, 6119, 8513, -34320, -93911, 146329, 803706, -220597, -5846539, -4302360, 36623413, 66739933, -189623958, -656803489, 670564217, 5268188640, 574239121, -36303081359, -40322755206, 213798814307

Offset: 0

Philippe Deléham, Oct 26 2008

Row sums of Riordan array (1,x(1-7x)).

G. C. Greubel, Table of n, a(n) for n = 0..1500
Taras Goy and Mark Shattuck, Determinants of Toeplitz-Hessenberg Matrices with Generalized Leonardo Number Entries, Ann. Math. Silesianae (2023). See p. 17.
Index entries for linear recurrences with constant coefficients, signature (1,-7).

Cf. A010892, A107920, A106852, A106853, A106854, A145934.

I:=[1,1]; [n le 2 select I[n] else Self(n-1) - 7*Self(n-2): n in [1..30]]; // G. C. Greubel, Jan 19 2018

Join[{a=1,b=1},Table[c=b-7*a;a=b;b=c,{n,80}]] (* Vladimir Joseph Stephan Orlovsky, Jan 22 2011 *)
CoefficientList[Series[1/(1-x(1-7x)),{x,0,50}],x] (* or *) LinearRecurrence[{1,-7},{1,1},50] (* Harvey P. Dale, May 11 2011 *)

Vec(1/(1-x*(1-7*x)) + O(x^40)) \\ Michel Marcus, Jan 29 2016

[lucas_number1(n,1,7) for n in range(1, 29)] # Zerinvary Lajos, Apr 22 2009

a(n) = a(n-1) - 7*a(n-2), a(0)=1, a(1)=1.

a(n) = Sum_{k=0..n} A109466(n,k)*7^(n-k).

Corrected by Zerinvary Lajos, Apr 22 2009

Corrected by D. S. McNeil, Aug 20 2010

A145978 Expansion of 1/(1-x(1-8x)).

Original entry on oeis.org

1, 1, -7, -15, 41, 161, -167, -1455, -119, 11521, 12473, -79695, -179479, 458081, 1893913, -1770735, -16922039, -2756159, 132620153, 154669425, -906291799, -2143647199, 5106687193, 22255864785, -18597632759, -196644551039, -47863488967, 1525292919345

Offset: 0

Philippe Deléham, Oct 26 2008

Row sums of Riordan array (1,1(1-8x)).

G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (1,-8).

Cf. A010892, A107920, A106852, A106853, A106854, A145934, A145976.

I:=[1,1]; [n le 2 select I[n] else Self(n-1) - 8*Self(n-2): n in [1..30]]; // G. C. Greubel, Jan 19 2018

LinearRecurrence[{1,-8},{1,1},50] (* G. C. Greubel, Jan 29 2016 *)

Vec(1/(1-x*(1-8*x)) + O(x^40)) \\ Michel Marcus, Jan 29 2016

[lucas_number1(n,1,8) for n in range(1, 27)] # Zerinvary Lajos, Apr 22 2009

a(n) = a(n-1) - 8*a(n-2), a(0)=1, a(1)=1.

a(n) = Sum_{k=0..n} A109466(n,k)*8^(n-k).

A110517 Riordan array (1,x(1-3x)).

Original entry on oeis.org

1, 0, 1, 0, -3, 1, 0, 0, -6, 1, 0, 0, 9, -9, 1, 0, 0, 0, 27, -12, 1, 0, 0, 0, -27, 54, -15, 1, 0, 0, 0, 0, -108, 90, -18, 1, 0, 0, 0, 0, 81, -270, 135, -21, 1, 0, 0, 0, 0, 0, 405, -540, 189, -24, 1, 0, 0, 0, 0, 0, -243, 1215, -945, 252, -27, 1, 0, 0, 0, 0, 0, 0, -1458, 2835, -1512, 324, -30, 1, 0, 0, 0, 0, 0, 0, 729, -5103, 5670, -2268, 405

Offset: 0

Paul Barry, Jul 24 2005

Inverse is Riordan array (1,xc(3x)) [A110518]. Row sums are A106852. Diagonal sums are A106855.

Modulo 2, this sequence becomes A106344. - Philippe Deléham, Dec 19 2008

			Rows begin
1;
0, 1;
0, -3, 1;
0, 0, -6, 1;
0, 0, 9, -9, 1;
0, 0, 0, 27, -12, 1;
0, 0, 0, -27, 54, -15, 1;

G. C. Greubel, Table of n, a(n) for the first 50 rows, flattened

T[n_, k_] := (-3)^(n - k)*Binomial[k, n - k]; Table[T[n, k], {n, 0, 20}, {k, 0, n}] // Flatten (* G. C. Greubel, Aug 29 2017 *)

for(n=0,20, for(k=0,n, print1((-3)^(n-k)*binomial(k, n-k), ", "))) \\ G. C. Greubel, Aug 29 2017

Number triangle: T(n, k) = (-3)^(n-k)*binomial(k, n-k).

T(n,k) = A109466(n,k)*3^(n-k). - Philippe Deléham, Oct 26 2008

A110523 Expansion of (1 + x)/(1 + x + 3*x^2).

Original entry on oeis.org

1, 0, -3, 3, 6, -15, -3, 48, -39, -105, 222, 93, -759, 480, 1797, -3237, -2154, 11865, -5403, -30192, 46401, 44175, -183378, 50853, 499281, -651840, -846003, 2801523, -263514, -8141055, 8931597, 15491568, -42286359, -4188345, 131047422, -118482387, -274659879, 630107040, 193872597

Offset: 0

Paul Barry, Jul 24 2005

Row sums of number triangle A110522.

The sequence a(n) is conjugate with A214733 since the following alternative relations: either ((-1 + i*sqrt(11))/2)^n = a(n) + A214733(n)*(-1 + i*sqrt(11))/2 or ((-1 - i*sqrt(11))/2)^n = a(n) + A214733(n)*(-1 - i*sqrt(11))/2. We have a(n+1) = -3*A214733(n), A214733(n+1) = a(n) - A214733(n). We note that sequences A110512 and A001607 are conjugated in a similar way. The above relations are connected with the Gauss sums, for example if e := exp(i*2Pi/11) then e + e^3 + e^4 + e^5 + e^9 = (-1 + i*sqrt(11))/2, and e^2 + e^6 + e^7 + e^8 + e^10 = (-1 - i*sqrt(11))/2, which is equivalent to the system of sums: Sum_{k=1..5} cos(2Pi*k/11) = -1/2 and Sum_{k=1..5} sin(2Pi*k/11) = sqrt(11)/2, and which is equivalent to the system of products: P_{k=1..5} cos(2Pi*k/11) = -1/32 and P_{k=1..5} sin(2Pi*k/11) = sqrt(11)/32 - for details see Witula's book. Lastly we note that ((-1 + i*sqrt(11))/2)^n + ((-1 - i*sqrt(11))/2)^n = 2*a(n) - A214733(n). - Roman Witula, Jul 27 2012

Roman Witula, On Some Applications of Formulae for Unimodular Complex Numbers, Jacek Skalmierski's Press, Gliwice 2011.

G. C. Greubel, Table of n, a(n) for n = 0..1000
Taras Goy and Mark Shattuck, Determinants of Toeplitz-Hessenberg Matrices with Generalized Leonardo Number Entries, Ann. Math. Silesianae, Vol. 38, No. 2 (2024), pp. 284-313. See p. 298.
Index entries for linear recurrences with constant coefficients, signature (-1,-3).

Cf. A001607, A106852, A110512, A110522, A214733.

[n le 2 select 2-n else -(Self(n-1) +3*Self(n-2)): n in [1..50]]; // G. C. Greubel, Dec 28 2023

CoefficientList[Series[(1+x)/(1+x+3*x^2), {x,0,50}], x] (* G. C. Greubel, Aug 30 2017 *)
LinearRecurrence[{-1,-3},{1,0},40] (* Harvey P. Dale, Jul 02 2022 *)

my(x='x+O('x^50)); Vec((1+x)/(1+x+3*x^2)) \\ G. C. Greubel, Aug 30 2017

@CachedFunction # a = A110523
def a(n): return 1-n if n<2 else -a(n-1) -3*a(n-2)
[a(n) for n in range(41)] # G. C. Greubel, Dec 28 2023

a(n) = Sum_{k=0..n} Sum_{j=0..n} (-1)^(n-j)*C(n, j)*(-3)^(j-k)*C(k, j-k).
From Roman Witula, Jul 27 2012: (Start)
a(n+2) + a(n+1) + 3*a(n) = 0.
a(n+1) = (-1)^n*(3*i*sqrt(11)/11)*(((1 + i*sqrt(11))/2)^(n-1) - ((1 - i*sqrt(11))/2)^(n-1)). (End)
From G. C. Greubel, Dec 28 2023: (Start)
a(n) = (-1)^n*3^((n-1)/2)*( sqrt(3)*ChebyshevU(n, 1/(2*sqrt(3))) - ChebyshevU(n-1, 1/(2*sqrt(3))) ).
a(n) = A106852(n) - A106852(n-1).
a(n) = (-1)^n*( A214733(n+1) + A214733(n) ). (End)
E.g.f.: exp(-x/2)*(sqrt(11)*cos(sqrt(11)*x/2) + sin(sqrt(11)*x/2))/sqrt(11). - Stefano Spezia, Jul 27 2025

cp's OEIS Frontend

A177694 Triangle t(n,m) = p(n)/ (p(m)*p(n-m) ) read by rows, where p(n>=1) = 1, -1, 2, 10, 10, -160, -2080,.. are partial products of A106852.

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A190958 a(n) = 2a(n-1) - 10a(n-2), with a(0) = 0, a(1) = 1.

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A145978 Expansion of 1/(1-x(1-8x)).