A035513 Wythoff array read by falling antidiagonals.
1, 2, 4, 3, 7, 6, 5, 11, 10, 9, 8, 18, 16, 15, 12, 13, 29, 26, 24, 20, 14, 21, 47, 42, 39, 32, 23, 17, 34, 76, 68, 63, 52, 37, 28, 19, 55, 123, 110, 102, 84, 60, 45, 31, 22, 89, 199, 178, 165, 136, 97, 73, 50, 36, 25, 144, 322, 288, 267, 220, 157, 118, 81, 58, 41, 27, 233, 521
Offset: 1
A022086 Fibonacci sequence beginning 0, 3.
0, 3, 3, 6, 9, 15, 24, 39, 63, 102, 165, 267, 432, 699, 1131, 1830, 2961, 4791, 7752, 12543, 20295, 32838, 53133, 85971, 139104, 225075, 364179, 589254, 953433, 1542687, 2496120, 4038807, 6534927, 10573734, 17108661, 27682395, 44791056, 72473451, 117264507
Offset: 0
Comments
First differences of A111314. - Ross La Haye, May 31 2006
Pisano period lengths: 1, 3, 1, 6, 20, 3, 16, 12, 8, 60, 10, 6, 28, 48, 20, 24, 36, 24, 18, 60, ... . - R. J. Mathar, Aug 10 2012
For n>=6, a(n) is the number of edge covers of the union of two cycles C_r and C_s, r+s=n, with a single common vertex. - Feryal Alayont, Oct 17 2024
References
- A. T. Benjamin and J. J. Quinn, Proofs that really count: the art of combinatorial proof, M.A.A. 2003, id. 7,17.
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..1000
- Tanya Khovanova, Recursive Sequences
- Index entries for linear recurrences with constant coefficients, signature (1,1).
Crossrefs
Programs
-
Magma
[3*Fibonacci(n): n in [0..40]]; // Vincenzo Librandi, Dec 31 2016
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Maple
BB := n->if n=0 then 3; > elif n=1 then 0; > else BB(n-2)+BB(n-1); > fi: > L:=[]: for k from 1 to 34 do L:=[op(L),BB(k)]: od: L; # Zerinvary Lajos, Mar 19 2007 with (combinat):seq(sum((fibonacci(n,1)),m=1..3),n=0..32); # Zerinvary Lajos, Jun 19 2008
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Mathematica
LinearRecurrence[{1, 1}, {0, 3}, 40] (* Arkadiusz Wesolowski, Aug 17 2012 *) Table[Fibonacci[n + 4] + Fibonacci[n - 4] - 4 Fibonacci[n], {n, 0, 40}] (* Bruno Berselli, Dec 30 2016 *) Table[3 Fibonacci[n], {n, 0, 40}] (* Vincenzo Librandi, Dec 31 2016 *)
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PARI
a(n)=3*fibonacci(n) \\ Charles R Greathouse IV, Nov 06 2014
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SageMath
def A022086(n): return 3*fibonacci(n) print([A022086(n) for n in range(41)]) # G. C. Greubel, Apr 10 2025
Formula
a(n) = 3*Fibonacci(n).
a(n) = F(n-2) + F(n+2) for n>1, with F=A000045.
a(n) = round( ((6*phi-3)/5) * phi^n ) for n>2. - Thomas Baruchel, Sep 08 2004
a(n) = A119457(n+1,n-1) for n>1. - Reinhard Zumkeller, May 20 2006
G.f.: 3*x/(1-x-x^2). - Philippe Deléham, Nov 19 2008
a(n) = A187893(n) - 1. - Filip Zaludek, Oct 29 2016
E.g.f.: 6*sinh(sqrt(5)*x/2)*exp(x/2)/sqrt(5). - Ilya Gutkovskiy, Oct 29 2016
a(n) = F(n+4) + F(n-4) - 4*F(n), F = A000045. - Bruno Berselli, Dec 29 2016
A205193 T(n,k) = Number of (n+1) X (k+1) 0..1 arrays with the number of clockwise edge increases in every 2 X 2 subblock differing from each horizontal or vertical neighbor.
16, 24, 24, 48, 40, 48, 72, 64, 64, 72, 144, 104, 124, 104, 144, 216, 168, 160, 160, 168, 216, 432, 272, 292, 256, 292, 272, 432, 648, 440, 384, 384, 384, 384, 440, 648, 1296, 712, 708, 576, 736, 576, 708, 712, 1296, 1944, 1152, 928, 864, 896, 896, 864, 928, 1152
Offset: 1
Comments
Table starts
..16..24..48...72..144..216..432..648..1296..1944..3888..5832.11664.17496.34992
..24..40..64..104..168..272..440..712..1152..1864..3016..4880..7896.12776.20672
..48..64.124..160..292..384..708..928..1708..2240..4124..5408..9956.13056.24036
..72.104.160..256..384..576..864.1312..1984..3008..4544..6880.10400.15744.23808
.144.168.292..384..736..896.1568.1920..3392..4224..7520..9344.16608.20608.36608
.216.272.384..576..896.1408.2048.2944..4224..6144..8960.13184.19328.28416.41600
.432.440.708..864.1568.2048.3904.4608..7872..9216.15808.18944.32960.39936.69824
.648.712.928.1312.1920.2944.4608.7168.10240.14336.19968.28160.39936.57344.82432
Examples
Some solutions for n=4, k=3 ..1..0..0..1....0..1..1..0....1..1..1..0....0..0..1..1....1..1..0..0 ..0..1..1..0....0..1..1..1....0..1..1..0....0..0..1..1....1..1..0..0 ..1..1..1..0....1..0..1..1....1..0..0..1....1..1..0..0....0..0..1..1 ..1..1..0..1....1..1..0..1....0..0..0..1....1..1..0..0....0..0..1..1 ..1..0..1..1....1..1..1..0....0..0..1..0....0..0..1..0....1..1..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..1300
Crossrefs
Column 2 is A022091(n+3).
Formula
Empirical for column k:
k=1: a(n) = 3*a(n-2);
k=2: a(n) = a(n-1) +a(n-2);
k=3: a(n) = 2*a(n-2) +a(n-4) for n>5;
k=4: a(n) = a(n-1) +a(n-2) -a(n-3) +a(n-4) for n>6;
k=5: a(n) = 2*a(n-2) +a(n-6) for n>9;
k=6: a(n) = a(n-1) +a(n-2) -a(n-3) +a(n-4) -a(n-5) +a(n-6) for n>10;
k=7: a(n) = 2*a(n-2) +a(n-8) for n>13;
k=8: a(n) = a(n-1) +a(n-2) -a(n-3) +a(n-4) -a(n-5) +a(n-6) -a(n-7) +a(n-8) for n>14;
k=9: a(n) = 2*a(n-2) +a(n-10) for n>17;
k=10: a(n) = a(n-1) +a(n-2) -a(n-3) +a(n-4) -a(n-5) +a(n-6) -a(n-7) +a(n-8) -a(n-9) +a(n-10) for n>18;
k=11: a(n) = 2*a(n-2) +a(n-12) for n>21;
k=12: a(n) = a(n-1) +a(n-2) -a(n-3) +a(n-4) -a(n-5) +a(n-6) -a(n-7) +a(n-8) -a(n-9) +a(n-10) -a(n-11) +a(n-12) for n>22;
k=13: a(n) = 2*a(n-2) +a(n-14) for n>25;
k=14: a(n) = a(n-1) +a(n-2) -a(n-3) +a(n-4) -a(n-5) +a(n-6) -a(n-7) +a(n-8) -a(n-9) +a(n-10) -a(n-11) +a(n-12) -a(n-13) +a(n-14) for n>26;
k=15: a(n) = 2*a(n-2) +a(n-16) for n>29;
apparently:
k odd a(n) = 2*a(n-2) +a(n-k-1) for n>2k-1;
k even a(n) = a(n-1) +sum{i in 2..k}(-1^i*a(n-i)) for n>2k-2.
A258160 a(n) = 8*Lucas(n).
16, 8, 24, 32, 56, 88, 144, 232, 376, 608, 984, 1592, 2576, 4168, 6744, 10912, 17656, 28568, 46224, 74792, 121016, 195808, 316824, 512632, 829456, 1342088, 2171544, 3513632, 5685176, 9198808, 14883984, 24082792, 38966776, 63049568, 102016344, 165065912
Offset: 0
Links
- Bruno Berselli, Table of n, a(n) for n = 0..300
- Tanya Khovanova, Recursive Sequences: a(n) = a(n-1)+a(n-2).
- Index entries for linear recurrences with constant coefficients, signature (1,1).
Crossrefs
Programs
-
Magma
[8*Lucas(n): n in [0..40]];
-
Mathematica
Table[8 LucasL[n], {n, 0, 40}] CoefficientList[Series[8*(2 - x)/(1 - x - x^2), {x, 0, 50}], x] (* G. C. Greubel, Dec 21 2017 *)
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PARI
a(n)=([0,1; 1,1]^n*[16;8])[1,1] \\ Charles R Greathouse IV, Oct 07 2015
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Sage
[8*lucas_number2(n, 1, -1) for n in (0..40)]
Formula
G.f.: 8*(2 - x)/(1 - x - x^2).
a(n) = Fibonacci(n+6) - Fibonacci(n-6), where Fibonacci(-6..-1) = -8, 5, -3, 2, -1, 1 (see similar sequences listed in Crossrefs).
a(n) = Lucas(n+4) + Lucas(n) + Lucas(n-4), where Lucas(-4..-1) = 7, -4, 3, -1.
a(n) = a(n-1) + a(n-2) for n>1, a(0)=16, a(1)=8.
a(n) = 2*A156279(n).
a(n+1) = 4*A022112(n).
A193917 Triangular array: the self-fusion of (p(n,x)), where p(n,x)=sum{F(k+1)*x^(n-k) : 0<=k<=n}, where F=A000045 (Fibonacci numbers).
1, 1, 1, 1, 2, 3, 2, 3, 6, 9, 3, 5, 9, 15, 24, 5, 8, 15, 24, 40, 64, 8, 13, 24, 39, 64, 104, 168, 13, 21, 39, 63, 104, 168, 273, 441, 21, 34, 63, 102, 168, 272, 441, 714, 1155, 34, 55, 102, 165, 272, 440, 714, 1155, 1870, 3025, 55, 89, 165, 267, 440, 712, 1155
Offset: 0
Comments
See A193722 for the definition of fusion of two sequences of polynomials or triangular arrays. (Fusion is defined at A193822; fission, at A193742; see A202503 and A202453 for infinite-matrix representations of fusion and fission.)
First five rows of P (triangle of coefficients of polynomials p(n,x)):
1
1...1
1...1...2
1...1...2...3
1...1...2...3...5
First eight rows of A193917:
1
1...1
1...2...3
2...3...6...9
3...5...9...15...24
5...8...15..24...40...64
8...13..24..39...64...104..168
13..21..39..63...104..168..273..441
...
col 1: A000045
col 2: A000045
col 3: A022086
col 4: A022086
col 5: A022091
col 6: A022091
col 7: A022355
col 8: A022355
right edge, w(n,n): A064831
w(n,n-1): A001654
w(n,n-2): A064831
w(n,n-3): A059840
w(n,n-4): A080097
w(n,n-5): A080143
w(n,n-6): A080144
Examples
First six rows: 1 1...1 1...2...3 2...3...6....9 3...5...9....15...24 5...8...15...24...40...64
Programs
-
Mathematica
z = 12; p[n_, x_] := Sum[Fibonacci[k + 1]*x^(n - k), {k, 0, n}]; q[n_, x_] := p[n, x]; t[n_, k_] := Coefficient[p[n, x], x^k]; t[n_, 0] := p[n, x] /. x -> 0; w[n_, x_] := Sum[t[n, k]*q[n + 1 - k, x], {k, 0, n}]; w[-1, x_] := 1 g[n_] := CoefficientList[w[n, x], {x}] TableForm[Table[Reverse[g[n]], {n, -1, z}]] Flatten[Table[Reverse[g[n]], {n, -1, z}]] (* A193917 *) TableForm[Table[g[n], {n, -1, z}]] Flatten[Table[g[n], {n, -1, z}]] (* A193918 *)
A194000 Triangular array: the self-fission of (p(n,x)), where sum{F(k+1)*x^(n-k) : 0<=k<=n}, where F=A000045 (Fibonacci numbers).
1, 2, 3, 3, 5, 9, 5, 8, 15, 24, 8, 13, 24, 39, 64, 13, 21, 39, 63, 104, 168, 21, 34, 63, 102, 168, 272, 441, 34, 55, 102, 165, 272, 440, 714, 1155, 55, 89, 165, 267, 440, 712, 1155, 1869, 3025, 89, 144, 267, 432, 712, 1152, 1869, 3024, 4895, 7920, 144, 233
Offset: 0
Comments
See A193917 for the self-fusion of the same sequence of polynomials. (Fusion is defined at A193822; fission, at A193842; see A202503 and A202453 for infinite-matrix representations of fusion and fission.)
...
First five rows of P (triangle of coefficients of polynomials p(n,x)):
1
1...1
1...1...2
1...1...2...3
1...1...2...3...5
First eight rows of A194000:
1
2....3
3....5....9
5....8....15...24
8....13...24...39...64
13...21...29...63...104...168
21...34...63...102..168...272...441
34...55...102..165..272...440...714..1155
...
col 1: A000045
col 2: A000045
col 3: A022086
col 4: A022086
col 5: A022091
col 6: A022091
right edge, d(n,n): A064831
d(n,n-1): A059840
d(n,n-2): A080097
d(n,n-3): A080143
d(n,n-4): A080144
...
Examples
First six rows: 1 2....3 3....5....9 5....8....15...24 8....13...24...39...64 13...21...29...63...104...168 ... Referring to the matrix product for fission at A193842, the row (5,8,15,24) is the product of P(4) and QQ, where P(4)=(p(4,4), p(4,3), p(4,2), p(4,1))=(5,3,2,1); and QQ is the 4x4 matrix (1..1..2..3) (0..1..1..2) (0..0..1..1) (0..0..0..1).
Programs
-
Mathematica
z = 11; p[n_, x_] := Sum[Fibonacci[k + 1]*x^(n - k), {k, 0, n}]; q[n_, x_] := p[n, x]; p1[n_, k_] := Coefficient[p[n, x], x^k]; p1[n_, 0] := p[n, x] /. x -> 0; d[n_, x_] := Sum[p1[n, k]*q[n - 1 - k, x], {k, 0, n - 1}] h[n_] := CoefficientList[d[n, x], {x}] TableForm[Table[Reverse[h[n]], {n, 0, z}]] Flatten[Table[Reverse[h[n]], {n, -1, z}]] (* A194000 *) TableForm[Table[h[n], {n, 0, z}]] Flatten[Table[h[n], {n, -1, z}]] (* A194001 *)
A111733 a(n) = a(n-1) + a(n-2) + 7 where a(0) = a(1) = 1.
1, 1, 9, 17, 33, 57, 97, 161, 265, 433, 705, 1145, 1857, 3009, 4873, 7889, 12769, 20665, 33441, 54113, 87561, 141681, 229249, 370937, 600193, 971137, 1571337, 2542481, 4113825, 6656313, 10770145, 17426465, 28196617, 45623089, 73819713, 119442809
Offset: 0
Comments
This is the sequence A(1,1;1,1;7)of the family of sequences [a,b:c,d:k] considered by Gary Detlefs, and treated as A(a,b;c,d;k) in the W. Lang link given below. - Wolfdieter Lang, Oct 17 2010
Examples
a(2) = a(0) + a(1) + 7 = 1 + 1 + 7 = 9, which is the third term in the sequence.
Links
- Wolfdieter Lang, Notes on certain inhomogeneous three term recurrences.
- Index entries for linear recurrences with constant coefficients, signature (2,0,-1)
Programs
-
Magma
I:=[1,1,9]; [n le 3 select I[n] else 2*Self(n-1)-Self(n-3): n in [1..40]]; // Vincenzo Librandi, Sep 16 2015
-
Mathematica
a[0] := 1; a[1] := 1; a[n_] := a[n - 1] + a[n - 2] + 7; Table[a[n], {n, 0, 30}] (* Stefan Steinerberger, Mar 10 2006 *) LinearRecurrence[{2, 0, -1}, {1, 1, 9}, 40] (* Vincenzo Librandi, Sep 16 2015 *)
Formula
From R. J. Mathar, Jul 08 2009: (Start)
G.f.: (1-x+7*x^2)/((x-1)*(x^2+x-1)).
a(n) = 8*A000045(n+1) - 7 = 2*a(n-1) - a(n-3). (End)
a(n+1) - a(n) = A022091(n). - R. J. Mathar, Apr 22 2013
Extensions
More terms from Stefan Steinerberger, Mar 10 2006
More terms from Brian Lauer (bel136(AT)psu.edu), Apr 05 2006
Comments
Examples
References
Links
Crossrefs
Programs
Maple
Mathematica
PARI
Python
Python
Formula
Extensions