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.

Previous Showing 21-29 of 29 results.

A322091 Digits of one of the two 13-adic integers sqrt(-3).

Original entry on oeis.org

6, 3, 12, 6, 10, 7, 4, 4, 9, 8, 9, 2, 8, 5, 12, 3, 5, 4, 0, 6, 5, 1, 2, 6, 5, 9, 4, 9, 1, 1, 4, 6, 11, 3, 1, 12, 5, 2, 2, 6, 3, 11, 11, 8, 4, 5, 10, 10, 7, 9, 5, 7, 7, 7, 8, 0, 1, 0, 7, 7, 0, 9, 12, 10, 8, 1, 6, 1, 2, 10, 2, 9, 7, 2, 1, 10, 11, 4, 3, 5, 6
Offset: 0

Views

Author

Jianing Song, Nov 26 2018

Keywords

Comments

This square root of -3 in the 13-adic field ends with digit 6. The other, A322092, ends with digit 7.

Examples

			...36225C13B64119495621560453C582989447A6C36.
		

Crossrefs

Programs

  • PARI
    a(n) = truncate(sqrt(-3+O(13^(n+1))))\13^n

Formula

a(n) = (A322089(n+1) - A322089(n))/13^n.
For n > 0, a(n) = 12 - A322092(n).
This 13-adic integer is the 13-adic limit as n -> oo of the integer sequence {L(13^n,6)}, where L(n,x) denotes the n-th Lucas polynomial, the n-th row polynomial of A114525. - Peter Bala, Dec 05 2022

A322092 Digits of one of the two 13-adic integers sqrt(-3).

Original entry on oeis.org

7, 9, 0, 6, 2, 5, 8, 8, 3, 4, 3, 10, 4, 7, 0, 9, 7, 8, 12, 6, 7, 11, 10, 6, 7, 3, 8, 3, 11, 11, 8, 6, 1, 9, 11, 0, 7, 10, 10, 6, 9, 1, 1, 4, 8, 7, 2, 2, 5, 3, 7, 5, 5, 5, 4, 12, 11, 12, 5, 5, 12, 3, 0, 2, 4, 11, 6, 11, 10, 2, 10, 3, 5, 10, 11, 2, 1, 8, 9, 7, 6
Offset: 0

Views

Author

Jianing Song, Nov 26 2018

Keywords

Comments

This square root of -3 in the 13-adic field ends with digit 7. The other, A322091, ends with digit 6.

Examples

			...96AA70B9168BB38376AB76C879074A34388526097.
		

Crossrefs

Programs

  • PARI
    a(n) = truncate(-sqrt(-3+O(13^(n+1))))\13^n

Formula

a(n) = (A322090(n+1) - A322090(n))/13^n.
For n > 0, a(n) = 12 - A322091(n).
This 13-adic integer is the 13-adic limit as n -> oo of the integer sequence {L(13^n,7)}, where L(n,x) denotes the n-th Lucas polynomial, the n-th row polynomial of A114525. - Peter Bala, Dec 05 2022

A117938 Triangle, columns generated from Lucas Polynomials.

Original entry on oeis.org

1, 1, 1, 1, 2, 3, 1, 3, 6, 4, 1, 4, 11, 14, 7, 1, 5, 18, 36, 34, 11, 1, 6, 27, 76, 119, 82, 18, 1, 7, 38, 140, 322, 393, 198, 29, 1, 8, 51, 234, 727, 1364, 1298, 478, 47, 1, 9, 66, 364, 1442, 3775, 5778, 4287, 1154, 76, 1, 10, 83, 536, 2599, 8886, 19602, 24476, 14159, 2786, 123
Offset: 1

Views

Author

Gary W. Adamson, Apr 03 2006

Keywords

Comments

Companion triangle using Fibonacci polynomial generators = A073133. Inverse binomial transforms of the columns defines rows of A117937 (with some adjustments of offset).
A309220 is another version of the same triangle (except it omits the last diagonal), and perhaps has a clearer definition. - N. J. A. Sloane, Aug 13 2019

Examples

			First few rows of the triangle are:
  1;
  1, 1;
  1, 2,  3;
  1, 3,  6,   4;
  1, 4, 11,  14,   7;
  1, 5, 18,  36,  34,  11;
  1, 6, 27,  76, 119,  82,  18;
  1, 7, 38, 140, 322, 393, 198, 29;
  ...
For example, T(7,4) = 76 = f(4), x^3 + 3*x = 64 + 12 = 76.
		

Crossrefs

Cf. A000204 (diagonal), A059100 (column 3), A061989 (column 4).

Programs

  • Maple
    Lucas := proc(n,x) # see A114525
        option remember;
        if  n=0 then
            2;
        elif n =1 then
            x ;
        else
            x*procname(n-1,x)+procname(n-2,x) ;
        end if;
        expand(%) ;
    end proc:
    A117938 := proc(n::integer,k::integer)
        if k = 1 then
            1;
        else
            subs(x=n-k+1,Lucas(k-1,x)) ;
        end if;
    end proc:
    seq(seq(A117938(n,k),k=1..n),n=1..12) ; # R. J. Mathar, Aug 16 2019
  • Mathematica
    T[n_, k_]:= LucasL[k-1, n-k+1] - Boole[k==1];
    Table[T[n, k], {n, 12}, {k, n}]//Flatten (* G. C. Greubel, Oct 28 2021 *)
  • Sage
    def A117938(n,k): return 1 if (k==1) else round(2^(1-k)*( (n-k+1 + sqrt((n-k)*(n-k+2) + 5))^(k-1) + (n-k+1 - sqrt((n-k)*(n-k+2) + 5))^(k-1) ))
    flatten([[A117938(n,k) for k in (1..n)] for n in (1..12)]) # G. C. Greubel, Oct 28 2021

Formula

Columns are f(x), x = 1, 2, 3, ..., of the Lucas Polynomials: (1, defined different from A034807 and A114525); (x); (x^2 + 2); (x^3 + 3*x); (x^4 + 4*x^2 + 2); (x^5 + 5*x^3 + 5*x); (x^6 + 6*x^4 + 9*x^2 + 2); (x^7 + 7*x^5 + 14*x^3 + 7*x); ...

Extensions

Terms a(51) and a(52) corrected by G. C. Greubel, Oct 28 2021

A108045 Triangle read by rows: lower triangular matrix obtained by inverting the lower triangular matrix in A108044.

Original entry on oeis.org

1, 0, 1, -2, 0, 1, 0, -3, 0, 1, 2, 0, -4, 0, 1, 0, 5, 0, -5, 0, 1, -2, 0, 9, 0, -6, 0, 1, 0, -7, 0, 14, 0, -7, 0, 1, 2, 0, -16, 0, 20, 0, -8, 0, 1, 0, 9, 0, -30, 0, 27, 0, -9, 0, 1, -2, 0, 25, 0, -50, 0, 35, 0, -10, 0, 1, 0, -11, 0, 55, 0, -77, 0, 44, 0, -11, 0, 1, 2, 0, -36, 0, 105, 0, -112, 0, 54, 0, -12, 0, 1
Offset: 0

Views

Author

N. J. A. Sloane, Jun 02 2005

Keywords

Comments

Signed version of A114525. - Eric W. Weisstein, Apr 07 2017
For n >= 3, also the coefficients of the matching polynomial for the n-cycle graph C_n. - Eric W. Weisstein, Apr 07 2017
This triangle describes the Chebyshev transform of A100047 and following. Chebyshev transform of sequence b is c(n) = Sum_{k=1..n} a(n,k)*b(k). - Christian G. Bower, Jun 12 2005

Examples

			Triangle begins:
   1;
   0,  1;
  -2,  0,  1;
   0, -3,  0,  1;
   2,  0, -4,  0,  1;
		

Crossrefs

Cf. A114525 (unsigned version).
Cf. A127672.

Programs

  • Maple
    f:=(1-x^2)/(1+x^2): g:=x/(1+x^2): G:=simplify(f/(1-t*g)): Gser:=simplify(series(G,x=0,14)): P[0]:=1: for n from 1 to 12 do P[n]:=coeff(Gser,x^n) od: for n from 0 to 12 do seq(coeff(t*P[n],t^k),k=1..n+1) od; # yields sequence in triangular form # Emeric Deutsch, Jun 06 2005
  • Mathematica
    a[n_, k_] := SeriesCoefficient[(1-x^2)/(1+x^2-t*x), {x, 0, n}, {t, 0, k}]; a[0, 0] = 1; Table[a[n, k], {n, 0, 12}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jan 08 2014, after Emeric Deutsch *)
    Flatten[{{1}, CoefficientList[Table[I^n LucasL[n, -I x], {n, 10}], x]}] (* Eric W. Weisstein, Apr 07 2017 *)
    Flatten[{{1}, CoefficientList[LinearRecurrence[{x, -1}, {x, -2 + x^2}, 10], x]}] (* Eric W. Weisstein, Apr 07 2017 *)

Formula

Riordan array ( (1-x^2)/(1+x^2), x/(1+x^2)).
G.f.: (1-x^2)/(1+x^2-tx). - Emeric Deutsch, Jun 06 2005
From Peter Bala, Jun 29 2015: (Start)
Riordan array has the form ( x*h'(x)/h(x), h(x) ) with h(x) = x/(1 + x^2) and so belongs to the hitting time subgroup H of the Riordan group (see Peart and Woan).
T(n,k) = [x^(n-k)] f(x)^n with f(x) = ( 1 + sqrt(1 - 4*x^2) )/2.
In general the (n,k)th entry of the hitting time array ( x*h'(x)/h(x), h(x) ) has the form [x^(n-k)] f(x)^n, where f(x) = x/( series reversion of h(x) ). (End)

Extensions

More terms from Emeric Deutsch and Christian G. Bower, Jun 06 2005

A322089 One of the two successive approximations up to 13^n for 13-adic integer sqrt(-3). Here the 6 (mod 13) case (except for n = 0).

Original entry on oeis.org

0, 6, 45, 2073, 15255, 300865, 2899916, 22207152, 273201220, 7614777709, 92450772693, 1333177199334, 4917497987408, 191302178967256, 1705677711928521, 48954194340319989, 202511873382592260, 3529594919298491465, 38131258596823843197, 38131258596823843197, 8809653000849500507259
Offset: 0

Views

Author

Jianing Song, Nov 26 2018

Keywords

Comments

For n > 0, a(n) is the unique solution to x^2 == -3 (mod 13^n) in the range [0, 13^n - 1] and congruent to 6 modulo 13.
A322090 is the approximation (congruent to 7 mod 13) of another square root of -3 over the 13-adic field.

Examples

			6^2 = 36 = 3*13 - 3.
45^2 = 2025 = 12*13^2 - 3.
2073^2 = 4297329 = 1956*13^3 - 3.
		

Crossrefs

Programs

  • PARI
    a(n) = truncate(sqrt(-3+O(13^n)))

Formula

For n > 0, a(n) = 13^n - A322090(n).
a(n) = Sum_{i=0..n-1} A322091(i)*13^i.
a(n) = A286840(n)*A322086(n) mod 13^n = A286841(n)*A322085(n) mod 13^n.
a(n) == L(13^n,6) (mod 13^n) == (3 + sqrt(10))^(13^n) + (3 - sqrt(10))^(13^n) (mod 13^n), where L(n,x) denotes the n-th Lucas polynomial, the n-th row polynomial of A114525. - Peter Bala, Dec 05 2022

A322090 One of the two successive approximations up to 13^n for 13-adic integer sqrt(3). Here the 7 (mod 13) case (except for n = 0).

Original entry on oeis.org

0, 7, 124, 124, 13306, 70428, 1926893, 40541365, 542529501, 2989721664, 45407719156, 458983194703, 18380587135073, 111572927624997, 2231698673770768, 2231698673770768, 462904735800587581, 5120821000082846468, 74324148355133549932, 1423789031778622267480, 10195310774031298931542
Offset: 0

Views

Author

Jianing Song, Nov 26 2018

Keywords

Comments

For n > 0, a(n) is the unique solution to x^2 == -3 (mod 13^n) in the range [0, 13^n - 1] and congruent to 7 modulo 13.
A322089 is the approximation (congruent to 6 mod 13) of another square root of -3 over the 13-adic field.

Examples

			7^2 = 49 = 4*13 - 3.
124^2 = 15376 = 91*13^2 - 3 = 7*13^3 - 3.
13306^2 = 177049636 = 6199*13^4 - 3.
		

Crossrefs

Programs

  • PARI
    a(n) = truncate(-sqrt(-3+O(13^n)))

Formula

For n > 0, a(n) = 13^n - A322089(n).
a(n) = Sum_{i=0..n-1} A322092(i)*13^i.
a(n) = A286840(n)*A322085(n) mod 13^n = A286841(n)*A322086(n) mod 13^n.
a(n) == L(13^n,7) (mod 13^n) == ((7 + sqrt(53))/2)^(13^n) + ((7 - sqrt(53))/2)^(13^n) (mod 13^n), where L(n,x) denotes the n-th Lucas polynomial, the n-th row polynomial of A114525. - Peter Bala, Dec 05 2022

A352362 Array read by ascending antidiagonals. T(n, k) = L(k, n) where L are the Lucas polynomials.

Original entry on oeis.org

2, 2, 0, 2, 1, 2, 2, 2, 3, 0, 2, 3, 6, 4, 2, 2, 4, 11, 14, 7, 0, 2, 5, 18, 36, 34, 11, 2, 2, 6, 27, 76, 119, 82, 18, 0, 2, 7, 38, 140, 322, 393, 198, 29, 2, 2, 8, 51, 234, 727, 1364, 1298, 478, 47, 0, 2, 9, 66, 364, 1442, 3775, 5778, 4287, 1154, 76, 2
Offset: 0

Views

Author

Peter Luschny, Mar 18 2022

Keywords

Examples

			Array starts:
n\k 0, 1,  2,   3,    4,     5,      6,       7,        8, ...
--------------------------------------------------------------
[0] 2, 0,  2,   0,    2,     0,      2,       0,        2, ... A010673
[1] 2, 1,  3,   4,    7,    11,     18,      29,       47, ... A000032
[2] 2, 2,  6,  14,   34,    82,    198,     478,     1154, ... A002203
[3] 2, 3, 11,  36,  119,   393,   1298,    4287,    14159, ... A006497
[4] 2, 4, 18,  76,  322,  1364,   5778,   24476,   103682, ... A014448
[5] 2, 5, 27, 140,  727,  3775,  19602,  101785,   528527, ... A087130
[6] 2, 6, 38, 234, 1442,  8886,  54758,  337434,  2079362, ... A085447
[7] 2, 7, 51, 364, 2599, 18557, 132498,  946043,  6754799, ... A086902
[8] 2, 8, 66, 536, 4354, 35368, 287298, 2333752, 18957314, ... A086594
[9] 2, 9, 83, 756, 6887, 62739, 571538, 5206581, 47430767, ... A087798
A007395|A059100|
    A001477 A079908
		

Crossrefs

Cf. A320570 (main diagonal), A114525, A309220 (variant), A117938 (variant), A352361 (Fibonacci polynomials), A350470 (Jacobsthal polynomials).

Programs

  • Maple
    T := (n, k) -> (n/2 + sqrt((n/2)^2 + 1))^k + (n/2 - sqrt((n/2)^2 + 1))^k:
    seq(seq(simplify(T(n - k, k)), k = 0..n), n = 0..10);
  • Mathematica
    Table[LucasL[k, n], {n, 0, 9}, {k, 0, 9}] // TableForm
    (* or *)
    T[ 0, k_] := 2 Mod[k+1, 2]; T[n_, 0] := 2;
    T[n_, k_] := n^k Hypergeometric2F1[1/2 - k/2, -k/2, 1 - k, -4/n^2];
    Table[T[n, k], {n, 0, 9}, {k, 0, 8}] // TableForm
  • PARI
    T(n, k) = ([0, 1; 1, k]^n*[2; k])[1, 1] ;
    export(T)
    for(k = 0, 9, print(parvector(10, n, T(n - 1, k))))

Formula

T(n, k) = Sum_{j=0..floor(k/2)} binomial(k-j, j)*(k/(k-j))*n^(k-2*j) for k >= 1.
T(n, k) = (n/2 + sqrt((n/2)^2 + 1))^k + (n/2 - sqrt((n/2)^2 + 1))^k.
T(n, k) = [x^k] ((2 - n*x)/(1 - n*x - x^2)).
T(n, k) = n^k*hypergeom([1/2 - k/2, -k/2], [1 - k], -4/n^2) for n,k >= 1.

A277282 Max coefficient in n-th Lucas polynomial.

Original entry on oeis.org

2, 1, 2, 3, 4, 5, 9, 14, 20, 30, 50, 77, 112, 182, 294, 450, 672, 1122, 1782, 2717, 4290, 7007, 11011, 16744, 27456, 44200, 68952, 107406, 176358, 281010, 436050, 700910, 1136960, 1797818, 2778446, 4576264, 7354710, 11560835, 18349630, 29910465, 47720400
Offset: 0

Views

Author

Vladimir Reshetnikov, Oct 08 2016

Keywords

Examples

			For n = 6, L_6(x) = x^6 + 6*x^4 + 9*x^2 + 2, so a(6) = 9.
		

Crossrefs

Programs

  • Mathematica
    Table[Max@CoefficientList[LucasL[n, x], x], {n, 0, 40}]

A123185 Triangular array from a zero coefficient sum of recursive polynomials: p(k, x) = x*p(k - 1, x) + p(k - 2, x).

Original entry on oeis.org

1, -1, 1, 2, -3, 1, -1, 3, -3, 1, 2, -4, 4, -3, 1, -1, 5, -7, 5, -3, 1, 2, -5, 9, -10, 6, -3, 1, -1, 7, -12, 14, -13, 7, -3, 1, 2, -6, 16, -22, 20, -16, 8, -3, 1, -1, 9, -18, 30, -35, 27, -19, 9, -3, 1, 2, -7, 25, -40, 50, -51, 35, -22, 10, -3, 1
Offset: 0

Views

Author

Roger L. Bagula, Oct 02 2006

Keywords

Comments

Except for p(0,x)=1 all sum to zero: Table[Sum[CoefficientList[p[n, x], x][[m]], {m, 1, n + 1}], {n, 0, 12}] {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}

Examples

			1
-1, 1
2, -3, 1
-1, 3, -3, 1
2, -4, 4, -3, 1
-1, 5, -7, 5, -3, 1
2, -5, 9, -10, 6, -3, 1
		

Crossrefs

Programs

  • Maple
    S:= series((1 - t + (1-2*x)*t^2)/(1 - t*x - t^2), t, 21):
    R:= [seq(coeff(S,t,n),n=0..19)]:
    seq(seq(coeff(R[n],x,j),j=0..n-1),n=1..20); # Robert Israel, Jul 12 2016
  • Mathematica
    p[0, x] = 1; p[1, x] = x - 1; p[2, x] = x^2 - 3x + 2; p[k_, x_] := p[k, x] = x*p[k - 1, x] + p[k - 2, x] ; w = Table[CoefficientList[p[n, x], x], {n, 0, 10}]; Flatten[w]

Formula

p(k, x) = x*p(k - 1, x) + p(k - 2, x) for k >= 3 with p(0,x) = 1, p(1,x) = x-1 and p(2,x) = x^2-3x+2. (Corrected by Robert Israel, Jul 12 2016)
G.f.: g(t,x) = (1 - t + (1-2x) t^2)/(1 - t x - t^2). - Robert Israel, Jul 12 2016
For n >= 1, T(n,k) = A114525(n,k) + 2*A114525(n-1,k) - 5*A168561(n-1,k), where we take A114525(n-1,n) = A168561(n-1,n) = 0. - Robert Israel, Jul 13 2016

Extensions

Edited by Robert Israel, Jul 13 2016
Previous Showing 21-29 of 29 results.