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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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).

Original entry on oeis.org

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

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Author

Clark Kimberling, Aug 11 2011

Keywords

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
...
Suppose n is an odd positive integer and d(n+1,x) is the polynomial matched to row n+1 of A194000 as in the Mathematica program (and definition of fission at A193842), where the first row is counted as row 0.

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).
		

Crossrefs

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 *)

A286311 a(n) = 2*a(n-1) - a(n-2) + a(n-4), n>3, a(0)=0, a(1)=a(2)=1, a(3)=3.

Original entry on oeis.org

0, 1, 1, 3, 5, 8, 12, 19, 31, 51, 83, 134, 216, 349, 565, 915, 1481, 2396, 3876, 6271, 10147, 16419, 26567, 42986, 69552, 112537, 182089, 294627, 476717, 771344, 1248060, 2019403, 3267463, 5286867, 8554331, 13841198, 22395528, 36236725, 58632253, 94868979
Offset: 0

Views

Author

Paul Curtz, May 06 2017

Keywords

Comments

Difference table for a(n):
0, 1, 1, 3, 5, 8, 12, 19, 31, 51, 83, 134, 216, ...
1, 0, 2, 2, 3, 4, 7, 12, 20, 32, 51, 82, 133, ...
-1, 2, 0, 1, 1, 3, 5, 8, 12, 19, 31, 51, 83, ...
3, -2, 1, 0, 2, 2, 3, 4, 7, 12, 20, 32, 51, ...
etc.
The pair a(n) = 0, 1, 1, 3, 5, 8, 12, 19, 31, 51, ...
and b(n) = 0, 2, 2, 3, 4, 7, 12, 20, 32, 51, ...
is interesting. a(n) and b(n) are autosequences of the first kind (see Link). a(n) and b(n) have the same first trisection: 3*A001076(n).
a(n) + b(n) = A022086(n) = 3*A000045(n) (Fibonacci).
b(n) - a(n) = 0, 1, 1, 0, -1, -1, 0, ... = A128834(n).
a(n+6) - a(n) = b(n+6) - b(n) = 6*Fib(n+3).
a(n) - a(n) mod 9 = 9*A004699(n) = b(n) - b(n) mod 9.

Crossrefs

Programs

  • Magma
    I:=[0,1,1,3]; [n le 4 select I[n] else 2*Self(n-1) - Self(n-2) + Self(n-4): n in [1..30]]; // G. C. Greubel, Jan 15 2018
  • Mathematica
    LinearRecurrence[{2, -1, 0, 1}, {0, 1, 1, 3}, 40] (* or *)
    CoefficientList[Series[x (1 - x + 2 x^2)/((1 - x + x^2) (1 - x - x^2)), {x, 0, 39}], x] (* Michael De Vlieger, May 07 2017 *)
  • PARI
    concat(0, Vec(x*(1 - x + 2*x^2) / ((1 - x + x^2)*(1 - x - x^2)) + O(x^60))) \\ Colin Barker, May 06 2017
    

Formula

a(n) = 2*a(n-1) - a(n-2) + a(n-4). Valid for b(n).
G.f.: x*(1 - x + 2*x^2) / ((1 - x + x^2)*(1 - x - x^2)). - Colin Barker, May 06 2017

Extensions

More terms from Colin Barker, May 06 2017

A036605 a(n) = a(n-2) + 2*a(n-3) + a(n-4).

Original entry on oeis.org

1, 4, 4, 7, 13, 19, 31, 52, 82, 133, 217, 349, 565, 916, 1480, 2395, 3877, 6271, 10147, 16420, 26566, 42985, 69553, 112537, 182089, 294628, 476716, 771343, 1248061, 2019403, 3267463, 5286868, 8554330, 13841197, 22395529, 36236725
Offset: 0

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Author

Keywords

References

  • D. E. Knuth, Art of Computer Programming, Vol. 3, Sect. 5.4.2, Eq. (25).

Crossrefs

Cf. A004695.

Programs

Formula

3 * [Fibonacci(n+2)/2] + 1. - Ralf Stephan, Dec 02 2004
a(n) = (A099837(n+2)+A022086(n+2))/2. G.f. ( -1-4*x-3*x^2-x^3 ) / ( (1+x+x^2)*(x^2+x-1) ). - R. J. Mathar, Mar 21 2011

A036999 Restricted permutations.

Original entry on oeis.org

6, 9, 12, 18, 27, 42, 66, 105, 168, 270, 435, 702, 1134, 1833, 2964, 4794, 7755, 12546, 20298, 32841, 53136, 85974, 139107, 225078, 364182, 589257, 953436, 1542690, 2496123, 4038810, 6534930, 10573737, 17108664, 27682398, 44791059
Offset: 0

Views

Author

Keywords

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

Crossrefs

Equals A022086(n+3) + 3.

Programs

  • Magma
    [6] cat [3*Fibonacci(n+3)+3: n in [0..40]]; // Vincenzo Librandi, Jul 01 2017
  • Mathematica
    Join[{6}, Table[3 Fibonacci[n+3] + 3, {n, 0, 40}]] (* or *) CoefficientList[Series[3 (2 - x - 2 x^2) / ((x^2 + x - 1) (x - 1)), {x, 0, 33}], x] (* Vincenzo Librandi, Jul 01 2017 *)

Formula

G.f.: 3*(2-x-2*x^2)/((x^2+x-1)*(x-1)). - Vincenzo Librandi, Jul 01 2017

A099255 Expansion of g.f. (7+6*x-6*x^2-3*x^3)/((x^2+x-1)*(x^2-x-1)).

Original entry on oeis.org

7, 6, 15, 15, 38, 39, 99, 102, 259, 267, 678, 699, 1775, 1830, 4647, 4791, 12166, 12543, 31851, 32838, 83387, 85971, 218310, 225075, 571543, 589254, 1496319, 1542687, 3917414, 4038807, 10255923, 10573734, 26850355, 27682395, 70295142, 72473451
Offset: 0

Views

Author

Creighton Dement, Oct 09 2004

Keywords

Comments

One of two sequences involving the Lucas/Fibonacci numbers.
This sequence consists of pairs of numbers more or less close to each other with "jumps" in between pairs. "pos((Ex)^n)" sums up over all floretion basis vectors with positive coefficients for each n. The following relations appear to hold: a(2n) - (a(2n-1) + a(2n-2)) = 2*Luc(2n) a(2n+1) - a(2n) = Fib(2n), apart from initial term a(2n+1)/a(2n-1) -> 2 + golden ratio phi a(2n)/a(2n-2) -> 2 + golden ratio phi An identity: (1/2)a(n) - (1/2)A099256(n) = ((-1)^n)A000032(n)

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{0,3,0,-1},{7,6,15,15},40] (* Harvey P. Dale, Dec 29 2012 *)

Formula

a(n) = 2*pos((Ex)^n)
a(0) = 7, a(1) = 6, a(2) = a(3) = 15, a(n+4) = 3a(n+2) - a(n).
a(2n) = A022097(2n+1), a(2n+1) = A022086(2n+3).
a(n) = A061084(n+1)+A013655(n+2). [R. J. Mathar, Nov 30 2008]

Extensions

More terms from Creighton Dement, Apr 19 2005

A099256 Expansion of g.f. (3-x)*(1+3*x+x^2)/((1-x-x^2)*(1+x-x^2)).

Original entry on oeis.org

3, 8, 9, 23, 24, 61, 63, 160, 165, 419, 432, 1097, 1131, 2872, 2961, 7519, 7752, 19685, 20295, 51536, 53133, 134923, 139104, 353233, 364179, 924776, 953433, 2421095, 2496120, 6338509, 6534927, 16594432, 17108661, 43444787, 44791056, 113739929, 117264507, 297775000, 307002465, 779585071
Offset: 0

Views

Author

Creighton Dement, Oct 18 2004

Keywords

Comments

One of two sequences involving the Lucas/Fibonacci numbers. This sequence consists of pairs of numbers more or less close to each other with "jumps" in between pairs.
a(n+3) + a(n) - a(n+2) appears to be mysteriously connected with a(n+1).
Both this sequence and A099255 were created using "Floretion dynamical symmetries" (see link for further details).

Crossrefs

Cf. A000045, A099255, A000032, A055273 (bisection), A097134 (bisection).

Programs

  • Mathematica
    LinearRecurrence[{0,3,0,-1},{3,8,9,23},40] (* Harvey P. Dale, Apr 22 2012 *)

Formula

a(2n+2) - a(2n+1) = Fibonacci(2n-1).
A099255(n)/2 - a(n)/2 = (-1)^n*A000032(n)
a(0) = 3, a(1) = 8, a(2) = 9, a(3) = 23, a(n+4) = 3a(n+2) - a(n).
a(2n) = A022086(2n+2), a(2n+1) = A022097(2n+2).
a(n) = A013655(n+2)-A061084(n+1).

Extensions

Definition corrected, extended. - R. J. Mathar, Nov 13 2008

A199535 Clark Kimberling's even first column Stolarsky array read by antidiagonals.

Original entry on oeis.org

1, 2, 4, 3, 7, 6, 5, 11, 9, 10, 8, 18, 15, 17, 12, 13, 29, 24, 27, 19, 14, 21, 47, 39, 44, 31, 23, 16, 34, 76, 63, 71, 50, 37, 25, 20, 55, 123, 102, 115, 81, 60, 41, 33, 22, 89, 199, 165, 186, 131, 97, 66, 53, 35, 26, 144, 322, 267, 301, 212, 157, 107, 86, 57, 43, 28
Offset: 1

Views

Author

Casey Mongoven, Nov 07 2011

Keywords

Comments

The rows of the array can be seen to have the form A(n, k) = p(n)*Fibonacci(k) + q(n)*Fibonacci(k+1) where p(n) is the sequence {0, 1, 3, 3, 3, 5, 7, 7, 9, 9, 11, 11, 13, 13, 15, 15, 17, ...}{n >= 1} and q(n) is the sequence {1, 3, 3, 7, 2, 9, 9, 13, 13, 17, 17, 19, 19, 23, 23, 25, ...}{n >= 1}. - G. C. Greubel, Jun 23 2022

Examples

			The even first column stolarsky array (EFC array), northwest corner:
  1......2.....3.....5.....8....13....21....34....55....89...144 ... A000045;
  4......7....11....18....29....47....76...123...199...322...521 ... A000032;
  6......9....15....24....39....63...102...165...267...432...699 ... A022086;
  10....17....27....44....71...115...186...301...487...788..1275 ... A022120;
  12....19....31....50....81...131...212...343...555...898..1453 ... A013655;
  14....23....37....60....97...157...254...411...665..1076..1741 ... A000285;
  16....25....41....66...107...173...280...453...733..1186..1919 ... A022113;
  20....33....53....86...139...225...364...589...953..1542..2495 ... A022096;
  22....35....57....92...149...241...390...631..1021..1652..2673 ... A022130;
Antidiagonal rows (T(n, k)):
   1;
   2,   4;
   3,   7,   6;
   5,  11,   9,  10;
   8,  18,  15,  17, 12;
  13,  29,  24,  27, 19, 14;
  21,  47,  39,  44, 31, 23, 16;
  34,  76,  63,  71, 50, 37, 25, 20;
  55, 123, 102, 115, 81, 60, 41, 33, 22;
		

Crossrefs

Formula

From G. C. Greubel, Jun 23 2022: (Start)
T(n, 1) = A000045(n+1).
T(n, 2) = A000032(n+1), n >= 2.
T(n, 3) = A022086(n) = A097135(n), n >= 3.
T(n, 4) = A022120(n-2), n >= 4.
T(n, 5) = A013655(n-1), n >= 5.
T(n, 6) = A000285(n-2), n >= 6.
T(n, 7) = A022113(n-4), n >= 7.
T(n, 8) = A022096(n-4), n >= 8.
T(n, 9) = A022130(n-6), n >= 9.
T(n, 10) = A022098(n-5), n >= 10.
T(n, 11) = A022095(n-7), n >= 11.
T(n, 12) = A022121(n-8), n >= 12.
T(n, 13) = A022388(n-10), n >= 13.
T(n, 14) = A022122(n-10), n >= 14.
T(n, 15) = A022097(n-10), n >= 15.
T(n, 16) = A022088(n-10), n >= 16.
T(n, 17) = A022390(n-14), n >= 17.
T(n, n) = A199536(n).
T(n, n-1) = A199537(n-1), n >= 2. (End)

Extensions

More terms added by G. C. Greubel, Jun 23 2022

A286350 a(n) = 2*a(n-1) - a(n-2) + a(n-4) for n>3, a(0)=0, a(1)=a(2)=2, a(3)=3.

Original entry on oeis.org

0, 2, 2, 3, 4, 7, 12, 20, 32, 51, 82, 133, 216, 350, 566, 915, 1480, 2395, 3876, 6272, 10148, 16419, 26566, 42985, 69552, 112538, 182090, 294627, 476716, 771343, 1248060, 2019404, 3267464, 5286867, 8554330, 13841197, 22395528, 36236726, 58632254, 94868979
Offset: 0

Views

Author

Paul Curtz, May 08 2017

Keywords

Comments

This is b(n) in A286311(n). As mentioned in A286311, the pair A286311(n) and, here a(n), are autosequences of the first kind.

Crossrefs

Cf. A022086, A128834, A226956 (same recurrence), A286311.

Programs

  • Magma
    I:=[0,2,2,3]; [n le 4 select I[n] else 2*Self(n-1) - Self(n-2) + Self(n-4): n in [1..30]]; // G. C. Greubel, Jan 15 2018
  • Mathematica
    LinearRecurrence[{2, -1, 0, 1}, {0, 2, 2, 3}, 40] (* or *)
    CoefficientList[Series[x (2 - 2 x + x^2)/((1 - x + x^2) (1 - x - x^2)), {x, 0, 39}], x] (* Michael De Vlieger, May 09 2017 *)
  • PARI
    concat(0, Vec(x*(2 - 2*x + x^2) / ((1 - x + x^2)*(1 - x - x^2)) + O(x^60))) \\ Colin Barker, May 09 2017
    

Formula

a(n) = A286311(n) + A128834(n).
a(n) = A022086(n) - A286311(n).
a(n) = (A022086(n) + A128834(n))/2.
G.f.: x*(2 - 2*x + x^2) / ((1 - x + x^2)*(1 - x - x^2)). - Colin Barker, May 09 2017

Extensions

More terms from Colin Barker, May 09 2017

A026390 Expansion of (2 + x + x^2)/((1 - x)*(1 - x - x^2)).

Original entry on oeis.org

2, 5, 11, 20, 35, 59, 98, 161, 263, 428, 695, 1127, 1826, 2957, 4787, 7748, 12539, 20291, 32834, 53129, 85967, 139100, 225071, 364175, 589250, 953429, 1542683, 2496116, 4038803, 6534923, 10573730
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A022086.

Programs

Formula

a(n) = A022086(n+3) - 4.

A258121 Number of vertices of degree n in all Lucas cubes.

Original entry on oeis.org

2, 5, 15, 39, 102, 267, 699, 1830, 4791, 12543, 32838, 85971, 225075, 589254, 1542687, 4038807, 10573734, 27682395, 72473451, 189737958, 496740423, 1300483311, 3404709510, 8913645219, 23336226147, 61095033222, 159948873519, 418751587335, 1096305888486, 2870166078123
Offset: 0

Views

Author

Emeric Deutsch, Jun 23 2015

Keywords

Comments

Column sums of A245960.

Crossrefs

Programs

  • Magma
    I:=[2,5,15,39]; [n le 4 select I[n] else 3*Self(n-1)-Self(n-2): n in [1..30]]; // Vincenzo Librandi, Oct 19 2017
  • Maple
    g := (2-x)*(1+x^2)/(1-3*x+x^2): gser := series(g, x = 0, 35): seq(coeff(gser, x, n), n = 0 .. 32);
    with(combinat): 2, 5, seq(3*fibonacci(2*n+1), n = 2 .. 32);
  • Mathematica
    CoefficientList[Series[(2 - x)*(1 + x^2)/(1 - 3 x + x^2), {x, 0, 50}], x] (* G. C. Greubel, Oct 19 2017 *)
    Join[{2, 5}, LinearRecurrence[{3, -1}, {15, 39}, 30]] (* Vincenzo Librandi, Oct 19 2017 *)
  • PARI
    my(x='x+O('x^50)); Vec((2-x)*(1+x^2)/(1-3*x+x^2)) \\ G. C. Greubel, Oct 19 2017
    

Formula

G.f.: (2-x)*(1+x^2)/(1-3*x+x^2).
a(n) = 3*F(2n+1) = 3*A001519(n+1) = A022086(2n+1) for n>=2; F(n) = A000045(n) are the Fibonacci numbers.
a(n) = F(n-1)^2 + F(n)^2 + F(n+1)^2 + F(n+2)^2 for n > 1, where F(n) is the n-th Fibonacci number (A000045). - Amiram Eldar, Jan 11 2022
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