cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Previous Showing 31-39 of 39 results.

A328647 Irregular triangular array read by rows: row n shows the coefficients of this polynomial of degree n: (1/n!)*(numerator of n-th derivative of (1+x)/(x^2-3x+1)).

Original entry on oeis.org

1, 1, 4, -2, -1, 11, -12, 3, 1, 29, -44, 24, -4, -1, 76, -145, 110, -40, 5, 1, 199, -456, 435, -220, 60, -6, -1, 521, -1393, 1596, -1015, 385, -84, 7, 1, 1364, -4168, 5572, -4256, 2030, -616, 112, -8, -1, 3571, -12276, 18756, -16716, 9576, -3654, 924, -144
Offset: 0

Views

Author

Clark Kimberling, Nov 01 2019

Keywords

Comments

The first 201 polynomials are irreducible. Column 1 of the array: A002879 (odd-indexed Lucas numbers). Row sums: A000032 (Lucas numbers). Alternating row sums: essentially 5*A030191.

Examples

			First eight rows:
     1,     1;
     4,    -2,   -1;
    11,   -12,    3,     1;
    29,   -44,   24,    -4,   -1;
    76,  -145,  110,   -40,    5,    1;
   199,  -456,  435,  -220,   60,   -6,  -1;
   521, -1393, 1596, -1015,  385,  -84,   7,  1;
  1364, -4168, 5572, -4256, 2030, -616, 112, -8, -1;
First eight polynomials:
1 + x
4 - 2 x - x^2
11 - 12 x + 3 x^2 + x^3
29 - 44 x + 24 x^2 - 4 x^3 - x^4
76 - 145 x + 110 x^2 - 40 x^3 + 5 x^4 + x^5
199 - 456 x + 435 x^2 - 220 x^3 + 60 x^4 - 6 x^5 - x^6
521 - 1393 x + 1596 x^2 - 1015 x^3 + 385 x^4 - 84 x^5 + 7 x^6 + x^7
1364 - 4168 x + 5572 x^2 - 4256 x^3 + 2030 x^4 - 616 x^5 + 112 x^6 - 8 x^7 - x^8
		

Crossrefs

Programs

  • Mathematica
    g[x_, n_] := Numerator[ Factor[D[(1 + x)/(x^2 - 3 x + 1), {x, n}]]]
    Column[Expand[Table[g[x, n]/n!, {n, 0, 12}]]] (* polynomials *)
    h[n_] := CoefficientList[g[x, n]/n!, x]
    Table[h[n], {n, 0, 10}]
    Column[%]  (* A328647 array *)

A057281 Coefficient triangle of polynomials (falling powers) related to Fibonacci convolutions. Companion triangle to A057282.

Original entry on oeis.org

1, 5, 16, 20, 160, 300, 75, 1075, 4850, 6840, 275, 6100, 48175, 159650, 186120, 1000, 31550, 379700, 2168650, 5846700, 5916240, 3625, 153875, 2605175, 22426825, 103057800, 238437900, 215717040, 13125, 720375, 16273875, 195469125
Offset: 0

Views

Author

Wolfdieter Lang, Sep 13 2000

Keywords

Comments

The row polynomials are p(k,x) := sum(a(k,m)*x^(k-m),m=0..k), k=0,1,2,..
The k-th convolution of F0(n) := A000045(n+1), n >= 0, (Fibonacci numbers starting with F0(0)=1) with itself is Fk(n) := A037027(n+k,k) = (p(k-1,n)*(n+1)*F0(n+1) + q(k-1,n)*(n+2)*F0(n))/(k!*5^k), k=1,2,..., where the companion polynomials q(k,n) := sum(b(k,m)*n^(k-m),m=0..k), k >= 0, are the row polynomials of triangle b(k,m)= A057282(k,m).
a(k,0)= A030191(k), k >= 0.

Examples

			k=2: F2(n)=((5*n^2+21*n+16)*F(n+2)+(5*n^2+27*n+34)*F(n+1))/50, F(n)=A000045(n); see A001628.
		

Crossrefs

A084329 a(0)=0, a(1)=1, a(n)=20a(n-1)-20a(n-2).

Original entry on oeis.org

0, 1, 20, 380, 7200, 136400, 2584000, 48952000, 927360000, 17568160000, 332816000000, 6304956800000, 119442816000000, 2262757184000000, 42866287360000000, 812070603520000000, 15384086323200000000
Offset: 0

Views

Author

Benoit Cloitre, Jun 21 2003

Keywords

Crossrefs

Cf. A030191.

Programs

  • Mathematica
    Union[Flatten[NestList[{#[[2]],20(#[[2]]-#[[1]])}&,{0,1},20]]]  (* Harvey P. Dale, Feb 24 2011 *)
    LinearRecurrence[{20,-20},{0,1},20] (* Harvey P. Dale, Nov 29 2019 *)
  • PARI
    a(n)=(1/8)*sum(k=0,n,binomial(n,k)*fibonacci(6*k))
    
  • PARI
    a(n)=imag((6+8*quadgen(5))^n)/8

Formula

a(n)=(1/8)*sum(k=0, n, binomial(n, k)*F(6*k)) where F(k) denotes the k-th Fibonacci number.
G.f.: x/(1-20x+20x^2).

A098111 Inverse binomial transform of A098149.

Original entry on oeis.org

1, 0, -5, -25, -100, -375, -1375, -5000, -18125, -65625, -237500, -859375, -3109375, -11250000, -40703125, -147265625, -532812500, -1927734375, -6974609375, -25234375000, -91298828125, -330322265625, -1195117187500, -4323974609375, -15644287109375, -56601562500000
Offset: 0

Views

Author

Creighton Dement, Sep 23 2004

Keywords

Comments

A030191(n) + 2*a(n) + A093129(n+2) = 4*A093129(n+1). - Creighton Dement, Oct 18 2004
From Wolfdieter Lang, Oct 02 2013: (Start)
These numbers a(n) and those of A030191(n) =: b(n), both interspersed with zeros, appear in the formula for nonnegative powers of the algebraic number rho(10) := 2*cos(pi/10) = phi*sqrt(3-phi), with the golden section phi, in terms of the power basis of the number field Q(rho(10)) of degree 4 (see A187360, n=10). In a (regular) decagon rho(10) is the length ratio of a smallest diagonal to the side. rho(10)^n = sum(A(n,k)*rho(10)^k, k=0..3), with A(2*k+1,0) = 0, A(2*k,0) = a(k), k >= 0; A(2*k,1) = 0, A(2*k+1,1) = a(k), k >= 0; A(2*k+1,2) = 0, k >= 0, A(0,2) = 0, A(2*k,2) = b(k-1), k >= 1; and A(2*k,3) = 0, k >= 0, A(1,3) = 0, A(2*k+1,3) = b(k-1), k >= 1. (End)

Examples

			Powers of rho(10) in the Q(rho(10)) power basis for n = 5: rho(10)^5 = 0*1 + a(2)*rho(10) + 0*rho(10)^2 + b(1)*rho(10)^3 = -5*rho(10) + 5*rho(10)^3.  - _Wolfdieter Lang_, Oct 02 2013
		

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{5,-5},{1,0},40] (* Harvey P. Dale, Dec 08 2015 *)

Formula

G.f.: (1-5x)/(1-5x+5x^2).
From Wolfdieter Lang, Oct 02 2013: (Start)
a(n) = b(n) - 5*b(n-1), n >= 0, with b(n) = A030191(n) = (sqrt(5))^n*S(n, sqrt(5)), with Chebyshev S-polynomials (see A049310).
a(n) = 5*(a(n-1) - a(n-2)), n >= 1, a(-1) = 1 = a(0). (End)

Extensions

More terms from David Wasserman, Jan 16 2008

A202551 Triangle T(n,k), read by rows, given by (1, -1, 1, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (-1, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938.

Original entry on oeis.org

1, 1, -1, 0, -1, 1, -1, 1, 1, -1, -1, 3, -2, -1, 1, 0, 2, -5, 3, 1, -1, 1, -2, -2, 7, -4, -1, 1, 1, -5, 7, 1, -9, 5, 1, -1, 0, -3, 12, -15, 1, 11, -6, -1, 1, -1, 3, 3, -21, 26, -4, -13, 7, 1, -1
Offset: 0

Views

Author

Philippe Deléham, Dec 21 2011

Keywords

Comments

Riordan array (1/(1-x+x^2), x*(x-1)/(1-x+x^2)).

Examples

			Triangle begins :
1
1, -1
0, -1, 1
-1, 1, 1, -1
-1, 3, -2, -1, 1
0, 2, -5, 3, 1, -1
		

Crossrefs

Formula

T(n,k) = T(n-1,k) + T(n-2,k-1) - T(n-1,k-1) - T(n-2,k).
G.f.: 1/(1+(y-1)*x+(1-y)*x^2).
Sum_{k, 0<=k<=n} T(n,k)*x^k = A190873(n+1), A190871(n+1), A057086(n), A057085(n+1), A057084(n), A030240(n), A030192(n), A030191(n), A001787(n+1), A057083(n), A099087(n), A010892(n), A000007(n), (-1)^n*A000045(n+1) for x = -11, -10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2 respectively.

A084328 a(0)=0, a(1)=1; a(n) = 13*a(n-1) - 11*a(n-2).

Original entry on oeis.org

0, 1, 13, 158, 1911, 23105, 279344, 3377317, 40832337, 493669894, 5968552915, 72160819061, 872436565728, 10547906344793, 127525980259301, 1541810773578190, 18640754273664159, 225369887048273977
Offset: 0

Views

Author

Benoit Cloitre, Jun 21 2003

Keywords

Crossrefs

Cf. A030191.

Programs

  • Mathematica
    Join[{a=0,b=1},Table[c=13*b-11*a;a=b;b=c,{n,60}]] (* Vladimir Joseph Stephan Orlovsky, Jan 21 2011 *)
  • PARI
    a(n)=(1/5)*sum(k=0,n,binomial(n,k)*fibonacci(5*k));
    
  • Sage
    [lucas_number1(n,13,11) for n in range(0, 18)] # Zerinvary Lajos, Apr 29 2009

Formula

a(n) = (1/5)*Sum_{k=0..n} binomial(n, k)*F(5*k) where F(k) denotes the k-th Fibonacci number.
G.f.: x / (11*x^2-13*x+1). - Colin Barker, Jun 26 2013

A087426 a(n) = S(n,4) where S(n,m) = sum(k=0,n,binomial(n,k)*Fibonacci(m*k)).

Original entry on oeis.org

0, 3, 27, 216, 1701, 13365, 104976, 824499, 6475707, 50860872, 399466485, 3137450517, 24641856288, 193539651939, 1520080160859, 11938864580280, 93769059774789, 736471756750581, 5784324272782128, 45430672644283923
Offset: 0

Views

Author

Benoit Cloitre, Oct 23 2003

Keywords

Crossrefs

Cf. A001906 (S(n,1)), A030191 (S(n,2)).

Formula

a(n) = 9*a(n-1)-9*a(n-2).
a(n) = (1/sqrt(5))*(((9+3*sqrt(5))/2)^n-((9-3*sqrt(5))/2)^n).
a(n) = 3^n*F(2n). - Benoit Cloitre, Sep 13 2005
G.f.: 3*x / (9*x^2-9*x+1). - Colin Barker, Jun 26 2013
E.g.f.: 2*exp(9*x/2)*sinh(3*sqrt(5)*x/2)/sqrt(5). - Stefano Spezia, Feb 23 2025

A260304 a(n) = 5*a(n-1) - 5*a(n-2) for n>1, a(0)=2, a(1)=3.

Original entry on oeis.org

2, 3, 5, 10, 25, 75, 250, 875, 3125, 11250, 40625, 146875, 531250, 1921875, 6953125, 25156250, 91015625, 329296875, 1191406250, 4310546875, 15595703125, 56425781250, 204150390625, 738623046875, 2672363281250, 9668701171875, 34981689453125, 126564941406250
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 21 2015

Keywords

Comments

Lim_{n -> infinity} a(n + 1)/a(n) = 2 + phi = 3.6180339887..., where phi is the golden ratio (A001622).

Crossrefs

Cf. A093129: initial values 1,2; A081567: initial values 1,3.

Programs

  • Magma
    [n le 2 select n+1 else 5*Self(n-1)-5*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Nov 23 2015
    
  • Mathematica
    Table[((5 + 2 Sqrt[5]) ((5 - Sqrt[5])/2)^n + (5 - 2 Sqrt[5]) ((5 + Sqrt[5])/2)^n)/5, {n, 0, 30}]
    RecurrenceTable[{a[0] == 2, a[1] == 3, a[n] == 5 a[n - 1] - 5 a[n - 2]}, a, {n, 0, 30}] (* Bruno Berselli, Nov 23 2015 *)
  • PARI
    a(n)=([0,1; -5,5]^n*[2;3])[1,1] \\ Charles R Greathouse IV, Jul 26 2016

Formula

G.f.: (2 - 7*x)/(1 - 5*x + 5*x^2).
a(n) = ((5 + 2*sqrt(5))*((5 - sqrt(5))/2)^n + (5 - 2*sqrt(5))*((5 + sqrt(5))/2)^n)/5.
a(n) = 2*A030191(n) - 7*A030191(n-1). - Bruno Berselli, Nov 23 2015

Extensions

Edited by Bruno Berselli, Nov 23 2015

A336602 a(n) = 8*a(n-1) - 21*a(n-2) + 20*a(n-3) - 5*a(n-4), with initial terms a(0)=1, a(1)=7, a(2)=35, a(3)=154.

Original entry on oeis.org

1, 7, 35, 154, 632, 2487, 9529, 35875, 133471, 492538, 1807268, 6604891, 24069905, 87539199, 317907067, 1153307002, 4180842064, 15147734815, 54860799881, 198634274203, 719047882103, 2602540622106, 9418700937340, 34084040705539, 123335178991777, 446277892754167, 1614771692630099
Offset: 0

Views

Author

Peter Morris, Dec 20 2020

Keywords

Crossrefs

Extension of patterns illustrated in A001519, A033191, A033190, A094667, A030191, A094788.

Formula

G.f.: ( 1-x+x^3 ) / ( (5*x^2-5*x+1)*(x^2-3*x+1) ). - R. J. Mathar, May 05 2023

Extensions

Offset corrected by Jon E. Schoenfield, Feb 05 2021
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