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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A166153 a(n) = (7^n+14*(-8)^n)/15.

Original entry on oeis.org

1, -7, 63, -455, 3983, -29463, 252511, -1902439, 16043055, -122579639, 1020990719, -7885450503, 65060930767, -506646158935, 4150058281887, -32522243182247, 264925506967919, -2086171125173751, 16921999515377215
Offset: 0

Views

Author

Philippe Deléham, Oct 08 2009

Keywords

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{-1, 56}, {1, -7}, 50] (* G. C. Greubel, May 01 2016 *)

Formula

a(n) = 56*a(n-2)-a(n-1), a(0)= 1, a(1)= -7, for n>1.
G.f.: (1-6*x)/(1+x-56*x^2).
a(n) = Sum_{k=0..n} A112555(n,k)*(-8)^k.
E.g.f.: (1/15)*(exp(7*x) + 14*exp(-8*x)). - G. C. Greubel, May 01 2016

A220074 Triangle read by rows giving coefficients T(n,k) of [x^(n-k)] in Sum_{i=0..n} (x-1)^i, 0 <= n <= k.

Original entry on oeis.org

1, 1, 0, 1, -1, 1, 1, -2, 2, 0, 1, -3, 4, -2, 1, 1, -4, 7, -6, 3, 0, 1, -5, 11, -13, 9, -3, 1, 1, -6, 16, -24, 22, -12, 4, 0, 1, -7, 22, -40, 46, -34, 16, -4, 1, 1, -8, 29, -62, 86, -80, 50, -20, 5, 0, 1, -9, 37, -91, 148, -166, 130, -70, 25, -5, 1
Offset: 0

Views

Author

Mokhtar Mohamed, Dec 03 2012

Keywords

Comments

If the triangle is viewed as a square array S(m, k) = T(m+k, k), 0 <= m, 0 <= k, its first row is (1,0,1,0,1,...) with e.g.f. cosh(x), g.f. 1/(1-x^2) and subsequent rows have g.f. 1/((1+x)^n*(1-x^2)) (substitute x for -x in g.f. for A059259).
By column, S(m, k) is the coefficient of [x^m] in the generating function Sum_{i=0..k} (-1)^i/(1-x)^(i+1).
This is a rational generating function down column k with a power of (1-x) in the denominator; therefore column k is a polynomial in m respectively n. - Mathew Englander, May 14 2014
Column k multiplied by k! seems to correspond to row k of A054651, considered as a polynomial and then evaluated on the negative integers. For example, row 5 of A054651 represents the polynomial x^5 - 5*x^4 + 25*x^3 + 5*x^2 + 94*x + 120. Evaluating that for x = -1, x = -2, x = -3, ... gives (0, -360, -1440, -4080, -9600, -19920, -37680, ...) which is 5! times column 5 of this triangle. - Mathew Englander, May 23 2014
This triangle provides a solution to a question in the mathematics of gambling. For 0 < p < 1 and positive integers N and G with N < G, suppose you begin with N dollars and make repeated wagers, each time winning 1 dollar with probability p and losing 1 dollar with probability 1-p. You continue betting 1 dollar at a time until you have either G dollars (your Goal) or 0 (bankrupt). What is the probability of reaching your Goal before going bankrupt, as a function of p, N, and G? (This is a type of one-dimensional random walk.) Answer: Let Q_m_(x) be the polynomial whose coefficients are given by row m-1 of the triangle (e.g., Q_6_(x) = 1 - 4x + 7x^2 - 6x^3 + 3x^4). Then, the probability of reaching G dollars before going bankrupt is p^(G-N)*Q_N_(p)/Q_G_(p). - Mathew Englander, May 23 2014
From Paul Curtz, Mar 17 2017: (Start)
Consider the triangle Ja(n+1,k) (here, but generally Ja(n,k)) composed of the triangle a(n) prepended with a column of 0's, i.e.,
0;
0, 1;
0, 1, 0;
0, 1, -1, 1;
0, 1, -2, 2, 0;
0, 1, -3, 4, -2, 1;
0, 1, -4, 7, -6, 3, 0;
0, 1, -5, 11, -13, 9, -3, 1;
... .
The row sums are 0, 1, 1, ... = A057427(n), the most elementary autosequence of the first kind (a sequence of the first kind has 0's as main diagonal of its array of successive differences).
The row sums of the absolute values are A001045(n).
Ja applied to a sequence written in its reluctant form yields an autosequence of the first kind. Example: the reluctant form of A001045(n) is 0, 0, 1, 0, 1, 1, 0, 1, 1, 3, 0, 1, 1, 3, 5, ... = Jl.
Jl multiplied by Ja gives the triangle Jal:
0;
0, 1;
0, 1, 0;
0, 1, -1, 3;
0, 1, -2, 6, 0;
0, 1, -3, 12, -10, 11;
0, 1, -4, 21, -30, 33, 0;
0, 1, -5, 33, -65, 99, -63, 43;
... .
The row sums are A001045(n). (End)

Examples

			Triangle begins:
  1;
  1,   0;
  1,  -1,   1;
  1,  -2,   2,    0;
  1,  -3,   4,   -2,    1;
  1,  -4,   7,   -6,    3,    0;
  1,  -5,  11,  -13,    9,   -3,    1;
  1,  -6,  16,  -24,   22,  -12,    4,    0;
  1,  -7,  22,  -40,   46,  -34,   16,   -4,   1;
  1,  -8,  29,  -62,   86,  -80,   50,  -20,   5,   0;
  1,  -9,  37,  -91,  148, -166,  130,  -70,  25,  -5, 1;
  1, -10,  46, -128,  239, -314,  296, -200,  95, -30, 6, 0;
  ...
		

Crossrefs

Similar to the triangles A080242, A108561, A112555, A071920.
Cf. A000124 (column 2), A003600 (column 3), A223718 (column 4, conjectured), A257890 (column 5).

Programs

  • GAP
    Flat(List([0..12], n-> List([0..n], k-> Sum([0..k], j-> (-1)^j*Binomial(n-k+j, j))))); # G. C. Greubel, Feb 18 2019
  • Magma
    [[(&+[(-1)^j*Binomial(n-k+j, j): j in [0..k]]): k in [0..n]]: n in [0..12]]; // G. C. Greubel, Feb 18 2019
    
  • Maple
    A059259A := proc(n,k)
        1/(1+y)/(1-x-y) ;
        coeftayl(%,x=0,n) ;
        coeftayl(%,y=0,k) ;
    end proc:
    A059259 := proc(n,k)
        A059259A(n-k,k) ;
    end proc:
    A220074 := proc(i,j)
        (-1)^j*A059259(i,j) ;
    end proc: # R. J. Mathar, May 14 2014
  • Mathematica
    Table[Sum[(-1)^i*Binomial[n-k+i,i], {i, 0, k}], {n, 0, 12}, {k, 0, n} ]//Flatten (* Michael De Vlieger, Jan 27 2016 *)
  • PARI
    {T(n,k) = sum(j=0,k, (-1)^j*binomial(n-k+j,j))};
    for(n=0,12, for(k=0,n, print1(T(n,k), ", "))) \\ G. C. Greubel, Feb 18 2019
    
  • Sage
    [[sum((-1)^j*binomial(n-k+j,j) for j in (0..k)) for k in (0..n)] for n in (0..12)] # G. C. Greubel, Feb 18 2019
    

Formula

Sum_{k=0..n} T(n,k) = 1.
T(n,k) = Sum_{i=0..k} (-1)^i*binomial(n-k+i, i).
T(2*n,n) = (-1)^n*A026641(n).
T(n,k) = (-1)^k*A059259(n,k).
T(n,0) = 1, T(n,n) = (1+(-1)^n)/2, and T(n,k) = T(n-1,k) - T(n-1,k-1) for 0 < k < n. - Mathew Englander, May 24 2014

Extensions

Definition and comments clarified by Li-yao Xia, May 15 2014

A114700 Triangle T, read by rows, such that the m-th matrix power satisfies T^m = I + m*(T - I), where T(n,k) = [T^-1](n-1,k) + [T^-1](n-1,k-1) for n>k>0, with T(n,0)=T(n,n)=1 for n>=0 and I is the identity matrix.

Original entry on oeis.org

1, 1, 1, 1, 0, 1, 1, -1, 1, 1, 1, 0, 0, 0, 1, 1, -1, 0, 0, 1, 1, 1, 0, 1, 0, -1, 0, 1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 0, 2, 2, 0, -2, -2, 0, 1, 1, -1, -2, -4, -2, 2, 4, 2, 1, 1, 1, 0, 3, 6, 6, 0, -6, -6, -3, 0, 1, 1, -1, -3, -9, -12, -6, 6, 12, 9, 3, 1, 1, 1, 0, 4, 12, 21, 18, 0, -18, -21, -12, -4, 0, 1
Offset: 0

Views

Author

Paul D. Hanna, Feb 19 2006

Keywords

Comments

The rows of this triangle are symmetric up to sign. Row sums = 2 after row 0. Unsigned row sums = A116466. Row squared sums = A116467. Central terms of odd rows: T(2*n+1,n+1) = |A064310(n)|.

Examples

			Matrix inverse is: T^-1 = 2*I - T.
Matrix log is: log(T) = T - I.
Triangle T begins:
1;
1, 1;
1, 0, 1;
1,-1, 1, 1;
1, 0, 0, 0, 1;
1,-1, 0, 0, 1, 1;
1, 0, 1, 0,-1, 0, 1;
1,-1,-1,-1, 1, 1, 1, 1;
1, 0, 2, 2, 0,-2,-2, 0, 1;
1,-1,-2,-4,-2, 2, 4, 2, 1, 1;
1, 0, 3, 6, 6, 0,-6,-6,-3, 0, 1;
1,-1,-3,-9,-12,-6, 6, 12, 9, 3, 1, 1;
1, 0, 4, 12, 21, 18, 0,-18,-21,-12,-4, 0, 1; ...
The g.f. of column k, C_k(x), obeys the recurrence:
C_k = C_{k-1} + (-1)^k*x*(1+2*x)/(1-x)/(1+x)^k with C_0 = 1/(1-x);
so that column g.f.s continue as:
C_1 = C_0 - x*(1+2*x)/(1-x)/(1+x),
C_2 = C_1 + x*(1+2*x)/(1-x)/(1+x)^2,
C_3 = C_2 - x*(1+2*x)/(1-x)/(1+x)^3, ...
		

Crossrefs

Cf. A116466 (unsigned row sums), A116467 (row squared sums), A064310 (central terms); A112555 (variant).

Programs

  • PARI
    T(n,k)=local(x=X+X*O(X^n),y=Y+Y*O(Y^k));polcoeff(polcoeff( 1/(1-x*y)+ x*(1+x-2*x^2*y)/(1-x)/(1+x+x*y)/(1-x*y),n,X),k,Y)
    
  • PARI
    T(n,k)=local(M=matrix(n+1,n+1));for(r=1,n+1,for(c=1,r, M[r,c]=if(r==c,1,if(c==1,1,if(c>1, (2*M^0-M)[r-1,c-1])+(2*M^0-M)[r-1,c]))));return(M[n+1,k+1])

Formula

G.f.: A(x,y) = 1/(1-x*y)+ x*(1+x-2*x^2*y)/(1-x)/(1+x+x*y)/(1-x*y). G.f. of matrix power T^m: 1/(1-x*y)+ m*x*(1+x-2*x^2*y)/(1-x)/(1+x+x*y)/(1-x*y).

A116466 Unsigned row sums of triangle A114700.

Original entry on oeis.org

1, 2, 2, 4, 2, 4, 4, 8, 10, 20, 32, 64, 112, 224, 408, 816, 1514, 3028, 5680, 11360, 21472, 42944, 81644, 163288, 311896, 623792, 1196132, 2392264, 4602236, 9204472, 17757184, 35514368, 68680170, 137360340, 266200112, 532400224, 1033703056
Offset: 0

Views

Author

Paul D. Hanna, Feb 19 2006

Keywords

Comments

Both triangles A112555 and A114700 have the property that the m-th matrix power of the triangles satisfy T^m = I + m*(T - I). So it is curious that the row squared sums of A112555 is a bisection of the unsigned row sums of A114700.

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(1 + 2*x)*(2*(1 + x^2)/(1 - x^2) + x^2/(1 - 4*x^2)^(1/2))/(2 + x^2), {x, 0, 50}], x] (* Wesley Ivan Hurt, Feb 21 2017 *)
  • PARI
    a(n)=local(x=X+X*O(X^n)); polcoeff((1+2*x)*(2*(1+x^2)/(1-x^2)+x^2/(1-4*x^2)^(1/2))/(2+x^2),n,X)
    
  • PARI
    /* a(n) as the unsigned row sums of A114700 */ a(n)=sum(k=0,n,abs(polcoeff(polcoeff(1/(1-x*y)+ x*(1+x-2*x^2*y)/(1-x)/(1+x+x*y+x*O(x^n)+y*O(y^k))/(1-x*y),n,x),k,y)))

Formula

G.f.: (1+2*x)*( 2*(1+x^2)/(1-x^2) + x^2/(1-4*x^2)^(1/2) )/(2+x^2). Also, a(2*n+1) = 2*a(2*n), a(2*n) = A112556(n), where A112556 equals the row squared sums of triangle A112555.

A165458 a(0)=1, a(1)=4, a(n) = 12*a(n-2) - a(n-1).

Original entry on oeis.org

1, 4, 8, 40, 56, 424, 248, 4840, -1864, 59944, -82312, 801640, -1789384, 11409064, -32881672, 169790440, -564370504, 2601855784, -9374301832, 40596571240, -153088193224, 640247048104, -2477305366792, 10160269944040, -39887934345544, 161811173674024
Offset: 0

Views

Author

Philippe Deléham, Sep 20 2009

Keywords

Comments

a(n)/a(n-1) tends to -4.

Programs

  • GAP
    a:=[1,4];; for n in [3..27] do a[n]:=12*a[n-2]-a[n-1]; od; a; # Muniru A Asiru, Oct 21 2018
  • Magma
    [(8*3^n-(-4)^n)/7: n in [0..40]]; // G. C. Greubel, Oct 20 2018
    
  • Maple
    A165458:=n->(8*3^n-(-4)^n)/7: seq(A165458(n), n=0..40); # Wesley Ivan Hurt, May 26 2015
  • Mathematica
    LinearRecurrence[{-1,12},{1,4},30] (* Harvey P. Dale, Dec 26 2015 *)
  • PARI
    vector(40, n, n--; (8*3^n-(-4)^n)/7) \\ G. C. Greubel, Oct 20 2018
    
  • Python
    for n in range(0, 30): print(int((8*3**n-(-4)**n)/7), end=', ') # Stefano Spezia, Oct 21 2018
    

Formula

G.f.: (1+5*x)/(1+x-12*x^2).
a(n) = Sum_{k, k=0..n} A112555(n,k)*3^k.
a(n) = (8*3^n-(-4)^n)/7. - Klaus Brockhaus, Sep 26 2009
E.g.f.: (8*exp(3*x) - exp(-4*x))/7. - G. C. Greubel, Oct 20 2018

A165470 a(0)=1, a(1)=5, a(n) = 20*a(n-2) - a(n-1).

Original entry on oeis.org

1, 5, 15, 85, 215, 1485, 2815, 26885, 29415, 508285, 80015, 10085685, -8485385, 210199085, -379906785, 4583888485, -12182024185, 103859793885, -347500277585, 2424696155285, -9374701706985, 57868624812685, -245362658952385, 1402735155206085, -6309988334253785
Offset: 0

Views

Author

Philippe Deléham, Sep 20 2009

Keywords

Comments

a(n)/a(n-1) tends to -5.

Programs

  • GAP
    a:=[1,5];; for n in [3..25] do a[n]:=20*a[n-2]-a[n-1]; od; a; # Muniru A Asiru, Oct 21 2018
  • Magma
    [(10*4^n-(-5)^n)/9: n in [0..40]]; // G. C. Greubel, Oct 20 2018
    
  • Maple
    seq(coeff(series((1+6*x)/(1+x-20*x^2),x,n+1), x, n), n = 0 .. 25); # Muniru A Asiru, Oct 21 2018
  • Mathematica
    LinearRecurrence[{-1,20}, {1,5}, 40] (* G. C. Greubel, Oct 20 2018 *)
  • PARI
    vector(40, n, n--; (10*4^n-(-5)^n)/9) \\ G. C. Greubel, Oct 20 2018
    
  • Python
    for n in range(0, 30): print(int((10*4**n-(-5)**n)/9), end=', ') # Stefano Spezia, Oct 21 2018
    

Formula

G.f.: (1+6*x)/(1+x-20*x^2).
a(n) = Sum_{k=0..n} A112555(n,k)*4^k.
a(n) = (10*4^n-(-5)^n)/9. - Klaus Brockhaus, Sep 25 2009
E.g.f.: (10*exp(4*x) - exp(-5*x))/9. - G. C. Greubel, Oct 20 2018

A165491 a(0)=1, a(1)=6, a(n) = 30*a(n-2) - a(n-1).

Original entry on oeis.org

1, 6, 24, 156, 564, 4116, 12804, 110676, 273444, 3046836, 5156484, 86248596, 68445924, 2519011956, -465634236, 76035992916, -90005019996, 2371084807476, -5071235407356, 76203779631636, -228340841852316, 2514454230801396
Offset: 0

Views

Author

Philippe Deléham, Sep 21 2009

Keywords

Comments

a(n)/a(n-1) tends to -6.

Programs

  • GAP
    a:=[1,6];; for n in [3..22] do a[n]:=30*a[n-2]-a[n-1]; od; a; # Muniru A Asiru, Oct 21 2018
  • Magma
    [(12*5^n-(-6)^n)/11: n in [0..30]]; // G. C. Greubel, Oct 20 2018
    
  • Maple
    seq(coeff(series((1+7*x)/(1+x-30*x^2),x,n+1), x, n), n = 0 .. 22); # Muniru A Asiru, Oct 21 2018
  • Mathematica
    LinearRecurrence[{-1,30},{1,6},30] (* Harvey P. Dale, May 04 2012 *)
  • PARI
    vector(30, n, n--; (12*5^n-(-6)^n)/11) \\ G. C. Greubel, Oct 20 2018
    

Formula

G.f.: (1+7*x)/(1+x-30*x^2).
a(n) = Sum_{k=0..n} A112555(n,k)*5^k.
a(n) = (12*5^n-(-6)^n)/11. - Klaus Brockhaus, Sep 26 2009
E.g.f.: (12*exp(5*x) - exp(-6*x))/11. - G. C. Greubel, Oct 20 2018

A165505 a(0)=1, a(1)=7, a(n) = 42*a(n-2) - a(n-1).

Original entry on oeis.org

1, 7, 35, 259, 1211, 9667, 41195, 364819, 1365371, 13957027, 43388555, 542806579, 1279512731, 21518363587, 32221171115, 871550099539, 481739087291, 36123365093347, -15890323427125, 1533071657347699, -2200465241286949
Offset: 0

Views

Author

Philippe Deléham, Sep 21 2009

Keywords

Comments

a(n)/a(n-1) tends to -7.

Programs

Formula

G.f.: (1+8*x)/(1+x-42*x^2).
a(n) = Sum_{k=0..n} A112555(n,k)*6^k.
a(n) = (14*6^n-(-7)^n)/13. - Klaus Brockhaus, Sep 26 2009
E.g.f.: (14*exp(6*x) - exp(-7*x))/13. - G. C. Greubel, Oct 20 2018

A165506 a(0) = 1, a(1) = 8, a(n) = 56*a(n-2) - a(n-1).

Original entry on oeis.org

1, 8, 48, 400, 2288, 20112, 108016, 1018256, 5030640, 51991696, 229724144, 2681810832, 10182741232, 139998665360, 430234843632, 7409690416528, 16683460826864, 398259202498704, 536014603805680, 21766500736121744
Offset: 0

Views

Author

Philippe Deléham, Sep 21 2009

Keywords

Comments

a(n)/a(n-1) tends to -8.

Examples

			a(20)=8250317076996336, a(21)=1210673724145821328, a(22)=-748655967834026512, a(23)=68546384520000020880, a(24)=-110471118718705505552,...
		

Programs

  • Magma
    [(16*7^n-(-8)^n)/15: n in [0..50]]; // G. C. Greubel, Oct 21 2018
  • Mathematica
    LinearRecurrence[{-1, 56}, {1, 8}, 50] (* G. C. Greubel, Oct 21 2018 *)
    CoefficientList[Series[-(1+9x)/(56x^2-x-1),{x,0,20}],x] (* Harvey P. Dale, Dec 20 2023 *)
  • PARI
    vector(50, n, n--; (16*7^n-(-8)^n)/15) \\ G. C. Greubel, Oct 21 2018
    

Formula

G.f.: (1+9*x)/(1+x-56*x^2).
a(n) = Sum_{k=0..n} A112555(n,k)*7^k.
a(n) = (16*7^n-(-8)^n)/15. - Klaus Brockhaus, Sep 26 2009
E.g.f.: (16*exp(7*x) - exp(-8*x))/15. - G. C. Greubel, Oct 21 2018

A165510 a(0)=1, a(1)=9, a(n) = 72*a(n-2) - a(n-1).

Original entry on oeis.org

1, 9, 63, 585, 3951, 38169, 246303, 2501865, 15231951, 164902329, 931798143, 10941169545, 56148296751, 731615910489, 3311061455583, 49365284099625, 189031140702351, 3365269314470649, 10244972816098623, 232054417825788105
Offset: 0

Views

Author

Philippe Deléham, Sep 21 2009

Keywords

Comments

a(n)/a(n-1) tends to -9.
First term < 0: a(27) = -60053864762402471338497.

Programs

  • Magma
    [(18*8^n-(-9)^n)/17: n in [0..30]]; // G. C. Greubel, Oct 21 2018
  • Mathematica
    LinearRecurrence[{-1,72},{1,9},30] (* Harvey P. Dale, Oct 15 2012 *)
  • PARI
    vector(30, n, n--; (18*8^n-(-9)^n)/17) \\ G. C. Greubel, Oct 21 2018
    

Formula

G.f.: (1+10*x)/(1+x-72*x^2).
a(n) = Sum_{k=0..n} A112555(n,k)*8^k.
a(n) = (18*8^n-(-9)^n)/17. - Klaus Brockhaus, Sep 26 2009
E.g.f.: (18*exp(8*x) - exp(-9*x))/17. - G. C. Greubel, Oct 21 2018
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