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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A127193 A 9th-order Fibonacci sequence.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 17, 33, 65, 129, 257, 513, 1025, 2049, 4097, 8185, 16353, 32673, 65281, 130433, 260609, 520705, 1040385, 2078721, 4153345, 8298505, 16580657, 33128641, 66192001, 132253569, 264246529, 527972353, 1054904321
Offset: 1

Views

Author

Luis A Restrepo (luisiii(AT)mac.com), Jan 07 2007

Keywords

Comments

9-Bonacci constant = 1.99802947...

Crossrefs

Cf. Fibonacci numbers A000045, tribonacci numbers A000213, tetranacci numbers A000288, pentanacci numbers A000322, hexanacci numbers A000383, 7th-order Fibonacci numbers A060455, octanacci numbers, A123526.

Programs

  • Mathematica
    LinearRecurrence[{1,1,1,1,1,1,1,1,1},{1,1,1,1,1,1,1,1,1},40] (* Ray Chandler, Aug 01 2015 *)
    With[{c=Table[1,{9}]},LinearRecurrence[c,c,40]] (* Harvey P. Dale, Apr 08 2016 *)
  • PARI
    x='x+O('x^50); Vec((x-x^2-x^3-x^4-x^5-x^6-x^7-x^8-x^9+7*x^10)/(1 -2*x+ x^10)) \\ G. C. Greubel, Jul 28 2017

Formula

For a(1)=...=a(9)=1, a(10)=9, a(n)= 2*a(n-1) - a(n-10). - Vincenzo Librandi, Dec 20 2010
G.f.: x*(1-x-x^2-x^3-x^4-x^5-x^6-x^7-x^8+7*x^9)/(1-2*x+x^10). - G. C. Greubel, Jul 28 2017

A214827 a(n) = a(n-1) + a(n-2) + a(n-3), with a(0) = 1, a(1) = a(2) = 5.

Original entry on oeis.org

1, 5, 5, 11, 21, 37, 69, 127, 233, 429, 789, 1451, 2669, 4909, 9029, 16607, 30545, 56181, 103333, 190059, 349573, 642965, 1182597, 2175135, 4000697, 7358429, 13534261, 24893387, 45786077, 84213725, 154893189, 284892991, 523999905
Offset: 0

Views

Author

Abel Amene, Jul 29 2012

Keywords

Comments

See comments in A214727.

Crossrefs

Programs

  • GAP
    a:=[1,5,5];; for n in [4..40] do a[n]:=a[n-1]+a[n-2]+a[n-3]; od; a; # G. C. Greubel, Apr 24 2019
  • Magma
    R:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1+4*x-x^2)/(1-x-x^2-x^3) )); // G. C. Greubel, Apr 24 2019
    
  • Mathematica
    LinearRecurrence[{1,1,1},{1,5,5},40] (* Ray Chandler, Dec 08 2013 *)
  • PARI
    my(x='x+O('x^40)); Vec((1+4*x-x^2)/(1-x-x^2-x^3)) \\ G. C. Greubel, Apr 24 2019
    
  • Sage
    ((1+4*x-x^2)/(1-x-x^2-x^3)).series(x, 40).coefficients(x, sparse=False) # G. C. Greubel, Apr 24 2019
    

Formula

G.f.: (x^2-4*x-1)/(x^3+x^2+x-1).
a(n) = -A000073(n) + 4*A000073(n+1) + A000073(n+2). - R. J. Mathar, Jul 29 2012

A214831 a(n) = a(n-1) + a(n-2) + a(n-3), with a(0) = 1, a(1) = a(2) = 9.

Original entry on oeis.org

1, 9, 9, 19, 37, 65, 121, 223, 409, 753, 1385, 2547, 4685, 8617, 15849, 29151, 53617, 98617, 181385, 333619, 613621, 1128625, 2075865, 3818111, 7022601, 12916577, 23757289, 43696467, 80370333, 147824089, 271890889, 500085311, 919800289, 1691776489
Offset: 0

Views

Author

Abel Amene, Aug 07 2012

Keywords

Comments

Part of a group of sequences defined by a(0), a(1)=a(2), a(n)=a(n-1)+a(n-2)+a(n-3) which is a subgroup of sequences with linear recurrences and constant coefficients listed in the index. See comments in A214727.

Crossrefs

Programs

  • GAP
    a:=[1,9,9];; for n in [4..40] do a[n]:=a[n-1]+a[n-2]+a[n-3]; od; a; # G. C. Greubel, Apr 24 2019
  • Magma
    R:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1+8*x-x^2)/(1-x-x^2-x^3) )); // G. C. Greubel, Apr 24 2019
    
  • Mathematica
    LinearRecurrence[{1,1,1},{1,9,9},40] (* Harvey P. Dale, Oct 11 2017 *)
  • PARI
    Vec((x^2-8*x-1)/(x^3+x^2+x-1) + O(x^40)) \\ Michel Marcus, Jul 08 2014
    
  • SageMath
    ((1+8*x-x^2)/(1-x-x^2-x^3)).series(x, 40).coefficients(x, sparse=False) # G. C. Greubel, Apr 24 2019
    

Formula

G.f.: (1+8*x-x^2)/(1-x-x^2-x^3).
a(n) = -A000073(n) + 8*A000073(n+1) + A000073(n+2). - G. C. Greubel, Apr 24 2019

A214828 a(n) = a(n-1) + a(n-2) + a(n-3), with a(0) = 1, a(1) = a(2) = 6.

Original entry on oeis.org

1, 6, 6, 13, 25, 44, 82, 151, 277, 510, 938, 1725, 3173, 5836, 10734, 19743, 36313, 66790, 122846, 225949, 415585, 764380, 1405914, 2585879, 4756173, 8747966, 16090018, 29594157, 54432141, 100116316, 184142614, 338691071, 622950001
Offset: 0

Views

Author

Abel Amene, Jul 30 2012

Keywords

Comments

See comments in A214727.

Crossrefs

Programs

  • GAP
    a:=[1,6,6];; for n in [4..40] do a[n]:=a[n-1]+a[n-2]+a[n-3]; od; a; # G. C. Greubel, Apr 24 2019
  • Magma
    R:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1+5*x-x^2)/(1-x-x^2-x^3) )); // G. C. Greubel, Apr 24 2019
    
  • Mathematica
    LinearRecurrence[{1,1,1},{1,6,6},33] (* Ray Chandler, Dec 08 2013 *)
  • PARI
    my(x='x+O('x^40)); Vec((1+5*x-x^2)/(1-x-x^2-x^3)) \\ G. C. Greubel, Apr 24 2019
    
  • Sage
    ((1+5*x-x^2)/(1-x-x^2-x^3)).series(x, 40).coefficients(x, sparse=False) # G. C. Greubel, Apr 24 2019
    

Formula

G.f.: (1+5*x-x^2)/(1-x-x^2-x^3).
a(n) = -A000073(n) + 5*A000073(n+1) + A000073(n+2). - G. C. Greubel, Apr 24 2019

A123526 Octanacci numbers.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 8, 15, 29, 57, 113, 225, 449, 897, 1793, 3578, 7141, 14253, 28449, 56785, 113345, 226241, 451585, 901377, 1799176, 3591211, 7168169, 14307889, 28558993, 57004641, 113783041, 227114497, 453327617, 904856058, 1806120905
Offset: 1

Views

Author

Danny Rorabaugh, Nov 10 2006

Keywords

Crossrefs

Cf. A254412, A254413. Indices of primes and primes in this sequence.

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 50);
    Coefficients(R!( x*(1-x^2-2*x^3-3*x^4-4*x^5-5*x^6-6*x^7)/(1-x-x^2-x^3-x^4-x^5-x^6-x^7-x^8) )); // G. C. Greubel, Mar 10 2021
  • Maple
    m:=50; S:=series( x*(1-x^2-2*x^3-3*x^4-4*x^5-5*x^6-6*x^7)/(1-x-x^2-x^3-x^4-x^5-x^6-x^7-x^8), x, m+1):
    seq(coeff(S, x, j), j=1..m); # G. C. Greubel, Mar 10 2021
  • Mathematica
    Module[{nn=8,lr},lr=PadRight[{},nn,1];LinearRecurrence[lr,lr,20]] (* Harvey P. Dale, Feb 04 2015 *)
  • PARI
    Vec(x*(1-x^2-2*x^3-3*x^4-4*x^5-5*x^6-6*x^7)/(1-x-x^2-x^3-x^4-x^5-x^6-x^7-x^8) + O(x^50)) \\ Colin Barker, Oct 19 2015
    
  • Sage
    @CachedFunction
    def A123526(n):
        if (n<9): return 1
        else: return sum(A(n-j) for j in (1..8))
    [A123526(n) for n in [1..50]] # G. C. Greubel, Mar 10 2021
    

Formula

a(n)=1 for 1 <= n <= 8, a(n) = a(n-1) + a(n-2) +...+ a(n-8) for n > 8.
G.f.: x*(1 -x^2 -2*x^3 -3*x^4 -4*x^5 -5*x^6 -6*x^7)/(1 -x -x^2 -x^3 -x^4 -x^5 -x^6 -x^7 -x^8). - Colin Barker, Oct 19 2015

A214829 a(n) = a(n-1) + a(n-2) + a(n-3), with a(0) = 1, a(1) = a(2) = 7.

Original entry on oeis.org

1, 7, 7, 15, 29, 51, 95, 175, 321, 591, 1087, 1999, 3677, 6763, 12439, 22879, 42081, 77399, 142359, 261839, 481597, 885795, 1629231, 2996623, 5511649, 10137503, 18645775, 34294927, 63078205, 116018907, 213392039, 392489151, 721900097, 1327781287, 2442170535
Offset: 0

Views

Author

Abel Amene, Aug 07 2012

Keywords

Comments

See comments in A214727.

Crossrefs

Programs

  • GAP
    a:=[1,7,7];; for n in [4..40] do a[n]:=a[n-1]+a[n-2]+a[n-3]; od; a; # G. C. Greubel, Apr 24 2019
  • Magma
    R:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1+6*x-x^2)/(1-x-x^2-x^3) )); // G. C. Greubel, Apr 24 2019
    
  • Mathematica
    LinearRecurrence[{1,1,1}, {1,7,7}, 40] (* G. C. Greubel, Apr 24 2019 *)
  • PARI
    Vec((x^2-6*x-1)/(x^3+x^2+x-1) + O(x^40)) \\ Michel Marcus, Jun 04 2017
    
  • Sage
    ((1+6*x-x^2)/(1-x-x^2-x^3)).series(x, 40).coefficients(x, sparse=False) # G. C. Greubel, Apr 24 2019
    

Formula

G.f.: (1+6*x-x^2)/(1-x-x^2-x^3).
a(n) = -A000073(n) + 6*A000073(n+1) + A000073(n+2). - G. C. Greubel, Apr 24 2019

A127194 A 10th-order Fibonacci sequence.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 10, 19, 37, 73, 145, 289, 577, 1153, 2305, 4609, 9217, 18424, 36829, 73621, 147169, 294193, 588097, 1175617, 2350081, 4697857, 9391105, 18772993, 37527562, 75018295, 149962969, 299778769, 599263345, 1197938593
Offset: 1

Views

Author

Luis A Restrepo (luisiii(AT)hotmail.com), Jan 11 2007

Keywords

Comments

10th-order Fibonacci constant = 1.999018633...

Crossrefs

Cf. Fibonacci numbers A000045, tribonacci numbers A000213, tetranacci numbers A000288, pentanacci numbers A000322, hexanacci numbers A000383, heptanacci numbers A060455, octanacci numbers A123526, 9th-order Fibonacci sequence A127193.

Programs

  • Mathematica
    With[{t=Table[1,{10}]},LinearRecurrence[t,t,40]] (* Harvey P. Dale, Nov 12 2013 *)
  • PARI
    a(n)=([0,1,0,0,0,0,0,0,0,0; 0,0,1,0,0,0,0,0,0,0; 0,0,0,1,0,0,0,0,0,0; 0,0,0,0,1,0,0,0,0,0; 0,0,0,0,0,1,0,0,0,0; 0,0,0,0,0,0,1,0,0,0; 0,0,0,0,0,0,0,1,0,0; 0,0,0,0,0,0,0,0,1,0; 0,0,0,0,0,0,0,0,0,1; 1,1,1,1,1,1,1,1,1,1]^(n-1)*[1;1;1;1;1;1;1;1;1;1])[1,1] \\ Charles R Greathouse IV, Jun 15 2015

Formula

O.g.f.: x*(-1+x^2+2*x^3+3*x^4+4*x^5+5*x^6+6*x^7+7*x^8+8*x^9) / (-1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9+x^10). - R. J. Mathar, Nov 23 2007

A127624 An 11th-order Fibonacci sequence: a(n) = a(n-1) + ... + a(n-11).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 21, 41, 81, 161, 321, 641, 1281, 2561, 5121, 10241, 20481, 40951, 81881, 163721, 327361, 654561, 1308801, 2616961, 5232641, 10462721, 20920321, 41830401, 83640321, 167239691, 334397501, 668631281
Offset: 1

Views

Author

Luis A Restrepo (Luisiii(AT)mac.com), Jan 19 2007

Keywords

Comments

The ratio a(n+1)/a(n) approaches the unique real root of r^11 = r^10 + ... + r + 1; r is about 1.99951040197828549144.
All terms have last digit 1.

Crossrefs

Cf. Fibonacci numbers A000045, tribonacci numbers A000213, tetranacci numbers A000288, pentanacci numbers A000322, hexanacci numbers A000383, heptanacci numbers A060455, octanacci numbers A123526, 9th-order Fibonacci sequence A127193, 10th-order Fibonacci sequence A127194.
Cf. A257966 (indices of primes in a), A257967 (primes in a).

Programs

  • Mathematica
    Module[{nn=11,lr},lr=PadRight[{},nn,1];LinearRecurrence[lr,lr,20]] (* Harvey P. Dale, Feb 04 2015 *)
  • PARI
    x='x+O('x^50); Vec(x*(-1+x^2+2*x^3+3*x^4+4*x^5+5*x^6+6*x^7+7*x^8 +8*x^9+9*x^10)/(-1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9+x^10+x^11)) \\ G. C. Greubel, Jul 28 2017

Formula

O.g.f: x*(-1+x^2+2*x^3+3*x^4+4*x^5+5*x^6+6*x^7+7*x^8+8*x^9+9*x^10) / (-1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9+x^10+x^11). - R. J. Mathar, Dec 02 2007

Extensions

Edited by Dean Hickerson, Mar 09 2007

A126116 a(n) = a(n-1) + a(n-3) + a(n-4), with a(0)=a(1)=a(2)=a(3)=1.

Original entry on oeis.org

1, 1, 1, 1, 3, 5, 7, 11, 19, 31, 49, 79, 129, 209, 337, 545, 883, 1429, 2311, 3739, 6051, 9791, 15841, 25631, 41473, 67105, 108577, 175681, 284259, 459941, 744199, 1204139, 1948339, 3152479, 5100817, 8253295, 13354113, 21607409, 34961521
Offset: 0

Views

Author

Luis A Restrepo (luisiii(AT)mac.com), Mar 05 2007

Keywords

Comments

This sequence has the same growth rate as the Fibonacci sequence, since x^4 - x^3 - x - 1 has the real roots phi and -1/phi.
The Ca1 sums, see A180662 for the definition of these sums, of triangle A035607 equal the terms of this sequence without the first term. - Johannes W. Meijer, Aug 05 2011

Examples

			G.f. = 1 + x + x^2 + x^3 + 3*x^4 + 5*x^5 + 7*x^6 + 11*x^7 + 19*x^8 + 31*x^9 + ...
		

References

  • S. Wolfram, A New Kind of Science. Champaign, IL: Wolfram Media, pp. 82-92, 2002

Crossrefs

Cf. Fibonacci numbers A000045; Lucas numbers A000032; tribonacci numbers A000213; tetranacci numbers A000288; pentanacci numbers A000322; hexanacci numbers A000383; 7th-order Fibonacci numbers A060455; octanacci numbers A079262; 9th-order Fibonacci sequence A127193; 10th-order Fibonacci sequence A127194; 11th-order Fibonacci sequence A127624, A128429.

Programs

  • GAP
    a:=[1,1,1,1];; for n in [5..50] do a[n]:=a[n-1]+a[n-3]+a[n-4]; od; a; # G. C. Greubel, Jul 15 2019
  • Magma
    [n le 4 select 1 else Self(n-1) + Self(n-3) + Self(n-4): n in [1..50]]; // Vincenzo Librandi, Dec 25 2015
    
  • Maple
    # From R. J. Mathar, Jul 22 2010: (Start)
    A010684 := proc(n) 1+2*(n mod 2) ; end proc:
    A000032 := proc(n) coeftayl((2-x)/(1-x-x^2),x=0,n) ; end proc:
    A126116 := proc(n) ((-1)^floor(n/2)*A010684(n)+2*A000032(n))/5 ; end proc: seq(A126116(n),n=0..80) ; # (End)
    with(combinat): A126116 := proc(n): fibonacci(n-1) + fibonacci(floor((n-4)/2)+1)* fibonacci(ceil((n-4)/2)+2) end: seq(A126116(n), n=0..38); # Johannes W. Meijer, Aug 05 2011
  • Mathematica
    LinearRecurrence[{1,0,1,1},{1,1,1,1},50] (* Harvey P. Dale, Nov 08 2011 *)
  • PARI
    Vec((x-1)*(1+x+x^2)/((x^2+x-1)*(x^2+1)) + O(x^50)) \\ Altug Alkan, Dec 25 2015
    
  • Sage
    ((1-x)*(1+x+x^2)/((1-x-x^2)*(1+x^2))).series(x, 50).coefficients(x, sparse=False) # G. C. Greubel, Jul 15 2019
    

Formula

From R. J. Mathar, Jul 22 2010: (Start)
G.f.: (1-x)*(1+x+x^2)/((1-x-x^2)*(1+x^2)).
a(n) = ( (-1)^floor(n/2) * A010684(n) + 2*A000032(n))/5.
a(2*n) = A061646(n). (End)
From Johannes W. Meijer, Aug 05 2011: (Start)
a(n) = F(n-1) + A070550(n-4) with F(n) = A000045(n).
a(n) = F(n-1) + F(floor((n-4)/2) + 1)*F(ceiling((n-4)/2) + 2). (End)
a(n) = (1/5)*((sqrt(5)-1)*(1/2*(1+sqrt(5)))^n - (1+sqrt(5))*(1/2*(1-sqrt(5)))^n + sin((Pi*n)/2) - 3*cos((Pi*n)/2)). - Harvey P. Dale, Nov 08 2011
(-1)^n * a(-n) = a(n) = F(n) - A070550(n - 6). - Michael Somos, Feb 05 2012
a(n)^2 + 3*a(n-2)^2 + 6*a(n-5)^2 + 3*a(n-7)^2 = a(n-8)^2 + 3*a(n-6)^2 + 6*a(n-3)^2 + 3*a(n-1)^2. - Greg Dresden, Jul 07 2021
a(n) = A293411(n)-A293411(n-1). - R. J. Mathar, Jul 20 2025

Extensions

Edited by Don Reble, Mar 09 2007

A214826 a(n) = a(n-1) + a(n-2) + a(n-3), with a(0) = 1, a(1) = a(2) = 4.

Original entry on oeis.org

1, 4, 4, 9, 17, 30, 56, 103, 189, 348, 640, 1177, 2165, 3982, 7324, 13471, 24777, 45572, 83820, 154169, 283561, 521550, 959280, 1764391, 3245221, 5968892, 10978504, 20192617, 37140013, 68311134, 125643764, 231094911, 425049809
Offset: 0

Views

Author

Abel Amene, Jul 29 2012

Keywords

Comments

See Comments in A214727.

Crossrefs

Programs

  • GAP
    a:=[1,4,4];; for n in [4..40] do a[n]:=a[n-1]+a[n-2]+a[n-3]; od; a; # G. C. Greubel, Apr 23 2019
  • Magma
    R:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1+3*x-x^2)/(1-x-x^2-x^3) )); // G. C. Greubel, Apr 23 2019
    
  • Mathematica
    LinearRecurrence[{1,1,1},{1,4,4},33] (* Ray Chandler, Dec 08 2013 *)
  • PARI
    my(x='x+O('x^40)); Vec((1+3*x-x^2)/(1-x-x^2-x^3)) \\ G. C. Greubel, Apr 23 2019
    
  • Sage
    ((1+3*x-x^2)/(1-x-x^2-x^3)).series(x, 40).coefficients(x, sparse=False) # G. C. Greubel, Apr 23 2019
    

Formula

G.f.: (1+3*x-x^2)/(1-x-x^2-x^3).
a(n) = K(n) - 2*T(n+1) + 5*T(n), where K(n) = A001644(n) and T(n) = A000073(n+1). - G. C. Greubel, Apr 23 2019
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