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.

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A039647 Related to A000032 (Lucas numbers): (n-1)!*L(n).

Original entry on oeis.org

1, 3, 8, 42, 264, 2160, 20880, 236880, 3064320, 44634240, 722131200, 12853209600, 249559833600, 5249378534400, 118911189196800, 2886037330176000, 74715282690048000, 2055161959538688000, 59855791774851072000, 1840125433884401664000, 59547709552131440640000
Offset: 1

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Author

Keywords

Comments

Number of possible well-colored circuits.

Crossrefs

a(n) = A039692(n, 1) (first column of Fibonacci Jabotinsky-triangle).

Programs

  • Mathematica
    nn=19;Drop[Range[0,nn]!CoefficientList[Series[Log[1/(1-x-x^2)],{x,0,nn}],x],1] (* Geoffrey Critzer, Jul 01 2013 *)

Formula

a(n) = (n-1)!*L(n), L(n) := A000032(n); E.g.f.: -log(1-x-x^2). Also a(n)/n! = sum(binomial(n-j, j)/(n-j), j=0..floor(n/2)).
a(n) = (n-1)*(a(n-1)+(n-2)*a(n-2)), for n > 2. - Christian Krause, Oct 15 2023

A060930 Third convolution of Lucas numbers A000032(n+1), n >= 0.

Original entry on oeis.org

1, 12, 70, 280, 905, 2568, 6666, 16220, 37580, 83780, 181074, 381488, 786715, 1593160, 3176210, 6246732, 12139859, 23344760, 44471340, 84005640, 157483176, 293201912, 542468100, 997906400, 1826073525
Offset: 0

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Author

Wolfdieter Lang, Apr 20 2001

Keywords

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 40);
    Coefficients(R!( ((1+2*x)/(1-x-x^2))^4 )); // G. C. Greubel, Apr 08 2021
    
  • Mathematica
    Table[((25*n^3+90*n^2+95*n+6)*LucasL[n+4] -12*(5*n^2+10*n-3)*LucasL[n+2])/150, {n, 0, 40}] (* G. C. Greubel, Apr 08 2021 *)
  • Sage
    def A060930_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( ((1+2*x)/(1-x-x^2))^4 ).list()
    A060930_list(40) # G. C. Greubel, Apr 08 2021

Formula

G.f.: ((1+2*x)/(1-x-x^2))^4.
a(n) = A060922(n+3, 3) (fourth column of Lucas triangle).
a(n) = (2*(25*n^3 + 60*n^2 + 35*n +24)*L(n+2) + (25*n^3 + 90*n^2 + 95*n + 6)*L(n+1))/(3!*5^2), with the Lucas numbers L(n) = A000032(n).

A075150 a(n) = L(n)*C(n), L(n)=Lucas numbers (A000032), C(n)=reflected Lucas numbers (see comment to A061084).

Original entry on oeis.org

4, -1, 9, -16, 49, -121, 324, -841, 2209, -5776, 15129, -39601, 103684, -271441, 710649, -1860496, 4870849, -12752041, 33385284, -87403801, 228826129, -599074576, 1568397609, -4106118241, 10749957124, -28143753121, 73681302249, -192900153616, 505019158609, -1322157322201
Offset: 0

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Author

Mario Catalani (mario.catalani(AT)unito.it), Sep 05 2002

Keywords

Crossrefs

Programs

  • Magma
    A075150:= func< n | (-1)^n*Lucas(n)^2 >; // G. C. Greubel, Jun 14 2025
    
  • Mathematica
    CoefficientList[Series[(4 + 7*x - x^2)/(1 + 2*x - 2*x^2 - x^3), {x, 0, 30}], x]
    LinearRecurrence[{-2,2,1},{4,-1,9},50] (* Harvey P. Dale, Nov 08 2011 *)
  • PARI
    a(n) = round((2+(1/2*(-3-sqrt(5)))^n+(1/2*(-3+sqrt(5)))^n)) \\ Colin Barker, Oct 01 2016
    
  • PARI
    Vec((4+7*x-x^2)/(1+2*x-2*x^2-x^3) + O(x^30)) \\ Colin Barker, Oct 01 2016
    
  • SageMath
    def A075150(n): return (-1)**n*lucas_number2(n,1,-1)**2 # G. C. Greubel, Jun 14 2025

Formula

a(n) = (-1)^n*A000032(2*n) + 2.
a(n) = -2*a(n-1) + 2*a(n-2) + a(n-3) with a(0)=4, a(1)=-1, a(2)=9.
G.f.: (4 + 7*x - x^2)/(1 + 2*x - 2*x^2 - x^3).
a(n) = (-1)^n*A001254(n). - R. J. Mathar, Jan 11 2012
a(n) = 2 + (1/2*(-3-sqrt(5)))^n + (1/2*(-3+sqrt(5)))^n. - Colin Barker, Oct 01 2016
From G. C. Greubel, Jun 14 2025: (Start)
a(n) = A000032(n)*A000032(-n) = (-1)^n*A000032(n)^2.
a(n) = A219233(n) + 2 + [n=0].
E.g.f.: 2*exp(-3*x/2)*cosh(sqrt(5)*x/2) + 2*exp(x). (End)

A099016 a(n) = 3*L(2*n)/5 - (-1)^n/5, where L = A000032.

Original entry on oeis.org

1, 2, 4, 11, 28, 74, 193, 506, 1324, 3467, 9076, 23762, 62209, 162866, 426388, 1116299, 2922508, 7651226, 20031169, 52442282, 137295676, 359444747, 941038564, 2463670946, 6449974273, 16886251874, 44208781348, 115740092171
Offset: 0

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Author

Paul Barry, Sep 22 2004

Keywords

Comments

Let M = an infinite triangle with (1,2,2,3,3,4,4,...) as the left border and all other columns = (0,1,2,3,4,5,...). Then lim_{n->infinity} M^n = A099016, the left-shifted vector considered as a sequence. - Gary W. Adamson, Jul 26 2010

Crossrefs

Cf. A000032.

Programs

  • Magma
    [3*Lucas(2*n)/5-(-1)^n/5: n in [0..35]]; // Vincenzo Librandi, Jun 09 2011
    
  • Magma
    F:=Fibonacci; [F(n+1)^2+F(n)*F(n-2): n in [0..30]]; // Bruno Berselli, Feb 15 2017
    
  • Maple
    with(combinat):seq(3*fibonacci(n)^2+(-1)^n, n= 0..27)
  • Mathematica
    CoefficientList[Series[(1 - 2*x^2)/((1 + x)*(1 - 3*x + x^2)), {x,0,50}], x] (* G. C. Greubel, Dec 31 2017 *)
  • PARI
    x='x+O('x^30); Vec((1 - 2*x^2)/((1 + x)*(1 - 3*x + x^2))) \\ G. C. Greubel, Dec 31 2017

Formula

G.f.: (1 - 2*x^2)/((1 + x)*(1 - 3*x + x^2)).
a(n) = 2*a(n-1) + 2*a(n-2) - a(n-3).
a(n) = 2*F(n)^2 + F(n)*F(n-1) + F(n-1)^2, where F = A000045.
a(n) = 3*((3/2 - sqrt(5)/2)^n + (3/2 + sqrt(5)/2)^n)/5 - (-1)^n/5.
a(n) = A099015(n)/F(n+1).
a(n) = 3*A005248(n)/5 - (-1)^n/5.
a(n) = 3*A000032(2*n)/5 - (-1)^n/5.
a(n) = A061646(n) + F(n)^2.
a(n) = 3*F(n)^2 + (-1)^n.
a(n) = F(n+1)^2 + F(n)*F(n-2). See also A192914, fourth formula. - Bruno Berselli, Feb 15 2017

A129729 Primes dividing numbers k such that k divides the k-th Lucas number A000032(k).

Original entry on oeis.org

2, 3, 107, 1283, 8747, 21401, 34667, 46187, 104003, 137387, 138563, 374929, 549547, 2204243, 2771281, 2808107, 11128427, 11223683, 13497443, 14880347, 21747529, 22753547, 23712683, 33697283, 44513387, 46970929, 57395627, 65898683
Offset: 1

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Author

Alexander Adamchuk, May 12 2007

Keywords

Comments

A prime p belongs to this sequence iff for some positive integer m, m*p divides A000032(m*p) or, alternatively, m*p belongs to A016089.
The minimum multiples from A016089 of listed primes are given by A140258.

Crossrefs

Extensions

Revised and extended by Max Alekseyev, May 16 2008

A153416 Decimal expansion of Sum_{n>=0} 1/A000032(2*n+1).

Original entry on oeis.org

1, 3, 9, 6, 6, 8, 0, 4, 9, 7, 3, 9, 8, 2, 6, 1, 2, 3, 2, 5, 9, 2, 8, 6, 5, 8, 0, 7, 4, 6, 3, 1, 2, 1, 5, 2, 2, 9, 1, 3, 4, 4, 8, 8, 1, 9, 2, 9, 6, 3, 1, 3, 8, 5, 0, 6, 3, 8, 3, 7, 0, 8, 2, 7, 1, 6, 2, 4, 8, 6, 0, 5, 3, 0, 1, 6, 2, 5, 1, 6, 9, 2, 3, 6, 4, 1, 8, 6, 2, 2, 0, 6, 6, 2, 2, 1, 6, 3, 6, 9, 5, 8, 0, 3, 4
Offset: 1

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Author

Eric W. Weisstein, Dec 25 2008

Keywords

Examples

			1.3966804973982612325...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[ NSum[ 1/LucasL[2*n + 1], {n, 0, Infinity}, WorkingPrecision -> 110, NSumTerms -> 100], 10, 105] // First (* Jean-François Alcover, Feb 07 2013 *)

Formula

From Amiram Eldar, Jul 05 2025: (Start)
Equals Sum_{n>=0} 1/A002878(n).
Equals A093540 - A153415. (End)

A156279 4 times the Lucas number A000032(n).

Original entry on oeis.org

8, 4, 12, 16, 28, 44, 72, 116, 188, 304, 492, 796, 1288, 2084, 3372, 5456, 8828, 14284, 23112, 37396, 60508, 97904, 158412, 256316, 414728, 671044, 1085772, 1756816, 2842588, 4599404, 7441992
Offset: 0

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Author

Paul Curtz, Feb 07 2009

Keywords

Comments

This is a second kind "autosequence" whose first kind companion is A022087. - Jean-François Alcover, Aug 20 2022

Crossrefs

Programs

Formula

a(n) = 4*A000032(n).
a(n) = a(n-1) + a(n-2).
a(n) = A014217(n+3) - A014217(n-3), with A014217(-5) = -11, A014217(-4) = 6, A014217(-3) = -4, A014217(-2) = 2, A014217(-1) = -1 extended as proposed in A153263.
G.f. 4*(-2 + x) / (-1 + x + x^2). - R. J. Mathar, Mar 11 2011
a(n) = Lucas(n+3) - Lucas(n-3), where Lucas(i) for i = 0..2 gives -4, 3, -1. - Bruno Berselli, Jul 27 2017

A191916 Ordered sums f+2g, where f and g are Lucas numbers (A000032 beginning at 1).

Original entry on oeis.org

3, 5, 6, 7, 9, 10, 11, 12, 13, 15, 17, 18, 19, 20, 21, 23, 24, 25, 26, 29, 31, 32, 33, 35, 37, 39, 40, 43, 47, 49, 51, 53, 54, 55, 59, 61, 62, 65, 69, 76, 78, 82, 83, 84, 87, 90, 95, 97, 98, 101, 105, 112, 123, 125, 129, 131, 134, 137, 141, 145, 153, 155
Offset: 1

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Author

Clark Kimberling, Jun 19 2011

Keywords

Crossrefs

Programs

  • Mathematica
    c = 1; d = 2; f[n_] := LucasL[n];
    g[n_] := c*f[n]; h[n_] := d*f[n];
    t[i_, j_] := h[i] + g[j];
    u = Table[t[i, j], {i, 1, 20}, {j, 1, 20}];
    v = Union[Flatten[u ]]    (* A191916 *)
    t1[i_, j_] := If[g[i] - h[j] > 0, g[i] - h[j], 0]
    u1 = Table[t1[i, j], {i, 1, 20}, {j, 1, 20}];
    v1 = Union[Flatten[u1 ]]  (* A191917: c*f(i)-d*f(j) *)
    g1[n_] := d*f[n]; h1[n_] := c*f[n];
    t2[i_, j_] := If[g1[i] - h1[j] > 0, g1[i] - h1[j], 0]
    u2 = Table[t2[i, j], {i, 1, 20}, {j, 1, 20}];
    v2 = Union[Flatten[u2 ]]  (* A191918: d*f(i)-c*f(j) *)
    v3 = Union[v1, v2]         (* A191919*)

A191920 Ordered sums f+3*g, where f and g are Lucas numbers (A000032 beginning at 1).

Original entry on oeis.org

4, 6, 7, 10, 12, 13, 14, 15, 16, 19, 20, 21, 22, 23, 24, 25, 27, 28, 30, 32, 34, 36, 37, 38, 39, 40, 41, 44, 50, 51, 55, 56, 57, 58, 59, 61, 62, 65, 68, 72, 79, 80, 83, 85, 88, 90, 91, 94, 97, 98, 101, 105, 109, 116, 126, 130, 132, 134, 135, 142, 144, 145
Offset: 1

Views

Author

Clark Kimberling, Jun 19 2011

Keywords

Crossrefs

Programs

  • Mathematica
    c = 1; d = 3; f[n_] := LucasL[n];
    g[n_] := c*f[n]; h[n_] := d*f[n];
    t[i_, j_] := h[i] + g[j];
    u = Table[t[i, j], {i, 1, 20}, {j, 1, 20}];
    v = Union[Flatten[u]]    (* A191920 *)
    t1[i_, j_] := If[g[i] - h[j] > 0, g[i] - h[j], 0]
    u1 = Table[t1[i, j], {i, 1, 20}, {j, 1, 20}];
    v1 = Union[Flatten[u1]]  (* A191921: c*f(i)-d*f(j) *)
    g1[n_] := d*f[n]; h1[n_] := c*f[n];
    t2[i_, j_] := If[g1[i] - h1[j] > 0, g1[i] - h1[j], 0]
    u2 = Table[t2[i, j], {i, 1, 20}, {j, 1, 20}];
    v2 = Union[Flatten[u2]]  (* A191922: d*f(i)-c*f(j) *)
    v3 = Union[v1, v2]       (* A191923 *)

A191921 Ordered sequence of nonnegative differences f-3*g, where f and g are Lucas numbers (A000032 beginning at 1).

Original entry on oeis.org

0, 1, 2, 4, 6, 8, 9, 14, 15, 17, 20, 22, 26, 35, 36, 38, 43, 44, 55, 58, 64, 67, 69, 73, 90, 94, 102, 111, 112, 114, 120, 145, 152, 166, 178, 181, 187, 190, 196, 235, 246, 268, 289, 293, 301, 310, 313, 319, 380, 398, 434, 467, 474, 488, 500, 509, 512, 518
Offset: 1

Views

Author

Clark Kimberling, Jun 19 2011

Keywords

Crossrefs

Programs

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