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.

Showing 1-5 of 5 results.

A307268 Partial sums of the Lucas numbers of the form L(3n+2) (A163063).

Original entry on oeis.org

3, 14, 61, 260, 1103, 4674, 19801, 83880, 355323, 1505174, 6376021, 27009260, 114413063, 484661514, 2053059121, 8696898000, 36840651123, 156059502494, 661078661101, 2800374146900, 11862575248703, 50250675141714, 212865275815561, 901711778403960, 3819712389431403
Offset: 0

Views

Author

Rigoberto Florez, Apr 01 2019

Keywords

Examples

			L(2) + L(5) = 14;
L(2) + L(5) + L(8) = 61;
L(2) + L(5) + L(8) + L(11) = 260.
		

Crossrefs

Programs

  • Mathematica
    Table[(LucasL[3*n + 4] - 1)/2, {n, 0, 20}]
    LinearRecurrence[{5,-3,-1},{3,14,61},30] (* Harvey P. Dale, Aug 10 2022 *)
  • PARI
    L(n) = fibonacci(n+1)+fibonacci(n-1);
    a(n) = (L(3*n+4)-1)/2; \\ Michel Marcus, Apr 01 2019
    
  • PARI
    Vec((3 - x) / ((1 - x)*(1 - 4*x - x^2)) + O(x^25)) \\ Colin Barker, Apr 02 2019

Formula

a(n) = A001076(n+1) + A099919(n+1).
a(n) = Sum_{i=0..n} L(3i+2), L(i) = A000032(i).
a(n) = (L(3*n+4)-1)/2.
From Colin Barker, Apr 02 2019: (Start)
G.f.: (3 - x) / ((1 - x)*(1 - 4*x - x^2)).
a(n) = (-2 + (7-3*sqrt(5))*(2-sqrt(5))^n + (2+sqrt(5))^n*(7+3*sqrt(5))) / 4.
a(n) = 5*a(n-1) - 3*a(n-2) - a(n-3) for n > 2.
(End)

A163114 a(n) = 5*a(n-2) for n > 2; a(1) = 3, a(2) = 5.

Original entry on oeis.org

3, 5, 15, 25, 75, 125, 375, 625, 1875, 3125, 9375, 15625, 46875, 78125, 234375, 390625, 1171875, 1953125, 5859375, 9765625, 29296875, 48828125, 146484375, 244140625, 732421875, 1220703125, 3662109375, 6103515625, 18310546875
Offset: 1

Views

Author

Klaus Brockhaus, Jul 21 2009

Keywords

Comments

Binomial transform is A163062, second binomial transform is A163063, third binomial transform is A098648 without initial 1, fourth binomial transform is A163064, fifth binomial transform is A163065.

Crossrefs

Programs

  • Magma
    [ n le 2 select 2*n+1 else 5*Self(n-2): n in [1..29] ];
    
  • Mathematica
    CoefficientList[Series[x*(3 + 5*x)/(1 - 5*x^2), {x, 0, 50}], x] (* G. C. Greubel, Dec 21 2017 *)
    LinearRecurrence[{0,5},{3,5},30] (* Harvey P. Dale, Aug 01 2021 *)
  • PARI
    x='x+O('x^30); Vec(x*(3+5*x)/(1-5*x^2)) \\ G. C. Greubel, Dec 21 2017

Formula

a(n) = (2-(-1)^n)*5^(1/4*(2*n-1+(-1)^n)).
G.f.: x*(3+5*x)/(1-5*x^2).
a(n) = A056487(n), n>=1.
E.g.f.: cosh(sqrt(5)*x) + 3*sinh(sqrt(5)*x)/sqrt(5) - 1. - Stefano Spezia, Nov 19 2023

A163062 a(n) = ((3+sqrt(5))*(1+sqrt(5))^n + (3-sqrt(5))*(1-sqrt(5))^n)/2.

Original entry on oeis.org

3, 8, 28, 88, 288, 928, 3008, 9728, 31488, 101888, 329728, 1067008, 3452928, 11173888, 36159488, 117014528, 378667008, 1225392128, 3965452288, 12832473088, 41526755328, 134383403008, 434873827328, 1407281266688
Offset: 0

Views

Author

Al Hakanson (hawkuu(AT)gmail.com), Jul 20 2009

Keywords

Comments

Binomial transform of A163114. Inverse binomial transform of A163063.

Crossrefs

Programs

  • Magma
    Z:=PolynomialRing(Integers()); N:=NumberField(x^2-5); S:=[ ((3+r)*(1+r)^n+(3-r)*(1-r)^n)/2: n in [0..23] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Jul 21 2009
    
  • Magma
    I:=[3,8]; [n le 2 select I[n] else 2*Self(n-1) + 4*Self(n-2): n in [1..30]]; // G. C. Greubel, Dec 22 2017
    
  • Mathematica
    CoefficientList[Series[(3+2*x)/(1-2*x-4*x^2), {x,0,50}], x] (* or *) LinearRecurrence[{2,4}, {3,8}, 30] (* G. C. Greubel, Dec 22 2017 *)
  • PARI
    x='x+O('x^30); Vec((3+2*x)/(1-2*x-4*x^2)) \\ G. C. Greubel, Dec 22 2017

Formula

a(n) = 2*a(n-1) + 4*a(n-2) for n > 1; a(0) = 3, a(1) = 8.
G.f.: (3+2*x)/(1-2*x-4*x^2).
a(n) = 2^n * A000032(n+2). - Diego Rattaggi, Jun 17 2020

Extensions

Edited and extended beyond a(5) by Klaus Brockhaus, Jul 21 2009

A332936 Number of blue nodes in n-th power graph W exponentiation of a cycle graph with 7 blue nodes and 1 green node.

Original entry on oeis.org

7, 51, 387, 2943, 22383, 170235, 1294731, 9847143, 74892951, 569602179, 4332138579, 32948302095, 250590001023, 1905875101899, 14495230812123, 110244221191287, 838468077093927, 6377011953177555, 48500691394138659, 368874495293576607, 2805493888166196879, 21337327619448845211
Offset: 0

Views

Author

George Strand Vajagich, Mar 02 2020

Keywords

Comments

The series of green nodes in n-th power W exponentiation for all n<6 n blue 1 green, 2 edge per node graphs already corresponds with an existing OEIS sequence (empirical). For example the number of blue nodes in n-th power W exponentiation of a square containing 3 blue nodes and 1 green node corresponds to A163063.

Examples

			For n = 2 take g(1)=15 and b(1)=51. Multiply b(1) by 7 to get 357 add 30 to get 387.
For n = 3 take g(2)=117 and b(2)=387. Multiply b(2) by 7 to get 774 add 234 to get 2943.
		

Crossrefs

Cf. A331211.

Programs

  • PARI
    Vec((1 + 43*x - 18*x^2) / (1 - 8*x + 3*x^2) + O(x^40)) \\ Colin Barker, Mar 03 2020
  • Python
    g=1
    b=7
    sg=0
    sb=0
    bl=[]
    gl=[]
    for int in range(1,20):
      sg=g*1+b*2
      sb=b*7+g*2
      g=sg
      b=sb
      gl.append(g)
      bl.append(b)
    print(bl)
    

Formula

g(n) = g(n-1) + 2*a(n-1), a(n) = 2*g(n-1) + 7*a(n-1) with g(0) = 1 and b(0) = 7, where g(n) = A332211(n).
From Colin Barker, Mar 03 2020: (Start)
G.f.: (1 + 43*x - 18*x^2) / (1 - 8*x + 3*x^2).
a(n) = 8*a(n-1) - 3*a(n-2) for n > 1.
(End)
From Stefano Spezia, Mar 03 2020: (Start)
a(n) = ((4 - sqrt(13))^n*(-23 + 7*sqrt(13)) + (4 + sqrt(13))^n*(23 + 7*sqrt(13)))/(2*sqrt(13)).
E.g.f.: exp(4*x)*(91*cosh(sqrt(13)*x) + 23*sqrt(13)*sinh(sqrt(13)*x))/13.
(End)
a(n) = 7*A190976(n+1) -5*A190976(n). - R. J. Mathar, Apr 30 2020

A122909 a(n) = F(n+1)*F(2n+2) + F(n)*F(2n).

Original entry on oeis.org

1, 4, 19, 79, 338, 1427, 6053, 25628, 108583, 459931, 1948354, 8253271, 34961561, 148099316, 627359147, 2657535383, 11257501522, 47687540107, 202007664157, 855718193164, 3624880442591, 15355239954179, 65045840274434
Offset: 0

Views

Author

Paul Barry, Sep 18 2006

Keywords

Comments

Let M be the matrix M(n,k)=F(k+1)*sum{j=0..n, (-1)^(n-j)C(n,j)C(j+1,k+1)}. a(n) gives the row sums of M^3.

Crossrefs

Programs

  • Mathematica
    Table[Fibonacci[n+1]Fibonacci[2n+2]+Fibonacci[n]Fibonacci[2n],{n,0,30}] (* or *) LinearRecurrence[{3,6,-3,-1},{1,4,19,79},30] (* Harvey P. Dale, Dec 11 2016 *)

Formula

G.f.: (1+x)*(1+x^2) / ( (x^2+4*x-1)*(x^2-x-1) ).
a(n) = (sqrt(5)+2)^n(sqrt(5)/5+3/5)-2^(-n-1)(sqrt(5)-1)^n(sqrt(5)/5+1/5)+ 2^(-n-1)(sqrt(5)+1)^n(sqrt(5)/5-1/5)(-1)^n+(sqrt(5)-2)^n(3/5-sqrt(5)/5)(-1)^n;
a(n) = (2*A163063(n) -A061084(n))/5. - R. J. Mathar, Jun 08 2016
Showing 1-5 of 5 results.