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.

Showing 1-10 of 10 results.

A176290 Hankel transform of A105872.

Original entry on oeis.org

1, 2, -3, -75, -650, -4507, -28267, -167406, -955271, -5310911, -28962586, -155616567, -826329687, -4345964510, -22675946635, -117526104883, -605643805098, -3105646720979, -15856669574339, -80653146223054
Offset: 0

Views

Author

Paul Barry, Apr 14 2010

Keywords

Crossrefs

Cf. A105872.

Programs

  • GAP
    a:=[1,2,-3,-75];; for n in [5..30] do a[n]:=10*a[n-1]-27*a[n-2]+10*a[n-3] -a[n-4]; od; a; # G. C. Greubel, Nov 25 2019
  • Magma
    R:=PowerSeriesRing(Integers(), 30); Coefficients(R!( (1-8*x+4*x^2-x^3)/(1-5*x+x^2)^2 )); // G. C. Greubel, Nov 25 2019
    
  • Maple
    seq(coeff(series((1-8*x+4*x^2-x^3)/(1-5*x+x^2)^2, x, n+1), x, n), n = 0..30); # G. C. Greubel, Nov 25 2019
  • Mathematica
    LinearRecurrence[{10,-27,10,-1},{1,2,-3,-75},30] (* Harvey P. Dale, Oct 29 2017 *)
  • PARI
    my(x='x+O('x^30)); Vec((1-8*x+4*x^2-x^3)/(1-5*x+x^2)^2) \\ G. C. Greubel, Nov 25 2019
    
  • Sage
    def A176290_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P((1-8*x+4*x^2-x^3)/(1-5*x+x^2)^2).list()
    A176290_list(30) # G. C. Greubel, Nov 25 2019
    

Formula

G.f.: (1-8*x+4*x^2-x^3)/(1-5*x+x^2)^2.

A360150 a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-k,n-3*k).

Original entry on oeis.org

1, 2, 6, 21, 77, 288, 1090, 4159, 15964, 61557, 238221, 924597, 3597290, 14024341, 54770176, 214218966, 838959762, 3289471537, 12910910288, 50720828034, 199422778415, 784672001097, 3089564308849, 12172411084432, 47984843655991, 189260578353602
Offset: 0

Views

Author

Seiichi Manyama, Jan 28 2023

Keywords

Crossrefs

Programs

  • Maple
    A360150 := proc(n)
        add(binomial(2*n-k,n-3*k),k=0..n/3) ;
    end proc:
    seq(A360150(n),n=0..70) ; # R. J. Mathar, Mar 12 2023
  • Mathematica
    a[n_] := Sum[Binomial[2*n - k, n - 3*k], {k, 0, Floor[n/3]}]; Array[a, 26, 0] (* Amiram Eldar, Jan 28 2023 *)
  • PARI
    a(n) = sum(k=0, n\3, binomial(2*n-k, n-3*k));
    
  • PARI
    my(N=30, x='x+O('x^N)); Vec(1/(sqrt(1-4*x)*(1-x^3*(2/(1+sqrt(1-4*x)))^5)))

Formula

G.f.: 1 / ( sqrt(1-4*x) * (1 - x^3 * c(x)^5) ), where c(x) is the g.f. of A000108.
a(n) ~ 2^(2*n+1) / sqrt(Pi*n). - Vaclav Kotesovec, Jan 28 2023
D-finite with recurrence n*a(n) +2*(-7*n+6)*a(n-1) +2*(36*n-61)*a(n-2) +4*(-41*n+103)*a(n-3) +(161*n-530)*a(n-4) +(-71*n+278)*a(n-5) +6*(2*n-9)*a(n-6)=0. - R. J. Mathar, Mar 12 2023
a(n) = [x^n] 1/(((1-x)^2-x^3) * (1-x)^(n-1)). - Seiichi Manyama, Apr 09 2024

A360152 a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-5*k,n-3*k).

Original entry on oeis.org

1, 2, 6, 21, 73, 262, 960, 3562, 13347, 50393, 191406, 730555, 2799622, 10765092, 41513751, 160490906, 621805286, 2413738744, 9385635299, 36550685683, 142534105563, 556514122937, 2175296066129, 8511430278018, 33334299581686, 130662787246407
Offset: 0

Views

Author

Seiichi Manyama, Jan 28 2023

Keywords

Crossrefs

Programs

  • Maple
    A360152 := proc(n)
        add(binomial(2*n-5*k,n-3*k),k=0..n/3) ;
    end proc:
    seq(A360152(n),n=0..70) ; # R. J. Mathar, Mar 12 2023
  • Mathematica
    a[n_] := Sum[Binomial[2*n - 5*k, n - 3*k], {k, 0, Floor[n/3]}]; Array[a, 26, 0] (* Amiram Eldar, Jan 28 2023 *)
  • PARI
    a(n) = sum(k=0, n\3, binomial(2*n-5*k, n-3*k));
    
  • PARI
    my(N=30, x='x+O('x^N)); Vec(1/(sqrt(1-4*x)*(1-2*x^3/(1+sqrt(1-4*x)))))

Formula

G.f.: 1 / ( sqrt(1-4*x) * (1 - x^3 * c(x)) ), where c(x) is the g.f. of A000108.
a(n) ~ 2^(2*n+5) / (31 * sqrt(Pi*n)). - Vaclav Kotesovec, Jan 28 2023
D-finite with recurrence 2*n*a(n) +4*(-2*n+1)*a(n-1) +(-3*n+4)*a(n-2) +2*(6*n-11)*a(n-3) +(n-4)*a(n-4) +2*(-n+9)*a(n-5) +4*(-2*n+1)*a(n-6) +(-n+4)*a(n-7) +2*(2*n-9)*a(n-8)=0. - R. J. Mathar, Mar 12 2023

A360153 a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-6*k,n-3*k).

Original entry on oeis.org

1, 2, 6, 21, 72, 258, 945, 3504, 13128, 49565, 188260, 718560, 2753721, 10588860, 40835160, 157871241, 611669250, 2374441380, 9233006541, 35956933050, 140220970200, 547490880981, 2140055896770, 8373651697800, 32795094564081, 128550662334522
Offset: 0

Views

Author

Seiichi Manyama, Jan 28 2023

Keywords

Crossrefs

Programs

  • Maple
    A360153 := proc(n)
        add(binomial(2*n-6*k,n-3*k),k=0..n/3) ;
    end proc:
    seq(A360153(n),n=0..70) ; # R. J. Mathar, Mar 12 2023
  • Mathematica
    a[n_] := Sum[Binomial[2*n - 6*k, n - 3*k], {k, 0, Floor[n/3]}]; Array[a, 26, 0] (* Amiram Eldar, Jan 28 2023 *)
  • PARI
    a(n) = sum(k=0, n\3, binomial(2*n-6*k, n-3*k));
    
  • PARI
    my(N=30, x='x+O('x^N)); Vec(1/(sqrt(1-4*x)*(1-x^3)))

Formula

G.f.: 1 / ( sqrt(1-4*x) * (1 - x^3) ).
a(n) ~ 2^(2*n + 6) / (63 * sqrt(Pi*n)). - Vaclav Kotesovec, Jan 28 2023
a(n)-a(n-3) = A000984(n). - R. J. Mathar, Mar 12 2023
D-finite with recurrence n*a(n) +2*(-2*n+1)*a(n-1) -n*a(n-3) +2*(2*n-1)*a(n-4)=0. - R. J. Mathar, Mar 12 2023

A360151 a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-4*k,n-3*k).

Original entry on oeis.org

1, 2, 6, 21, 74, 267, 981, 3648, 13690, 51744, 196699, 751237, 2880345, 11080081, 42743148, 165291569, 640563158, 2487083484, 9672626600, 37674470433, 146937686295, 573781535775, 2243050091905, 8777451670102, 34379401083017, 134770951530840
Offset: 0

Views

Author

Seiichi Manyama, Jan 28 2023

Keywords

Crossrefs

Programs

  • Maple
    A360151 := proc(n)
        add(binomial(2*n-4*k,n-3*k),k=0..n/3) ;
    end proc:
    seq(A360151(n),n=0..70) ; # R. J. Mathar, Mar 12 2023
  • Mathematica
    a[n_] := Sum[Binomial[2*n - 4*k, n - 3*k], {k, 0, Floor[n/3]}]; Array[a, 26, 0] (* Amiram Eldar, Jan 28 2023 *)
  • PARI
    a(n) = sum(k=0, n\3, binomial(2*n-4*k, n-3*k));
    
  • PARI
    my(N=30, x='x+O('x^N)); Vec(1/(sqrt(1-4*x)*(1-x^3*(2/(1+sqrt(1-4*x)))^2)))

Formula

G.f.: 1 / ( sqrt(1-4*x) * (1 - x^3 * c(x)^2) ), where c(x) is the g.f. of A000108.
a(n) ~ 2^(2*n+4) / (15*sqrt(Pi*n)). - Vaclav Kotesovec, Jan 28 2023
D-finite with recurrence +2*n*a(n) +(-11*n+6)*a(n-1) +(19*n-24)*a(n-2) +2*(-16*n+33)*a(n-3) +2*(11*n-36)*a(n-4) +(-25*n+78)*a(n-5) +6*(n-3)*a(n-6) +4*(-2*n+9)*a(n-7)=0. - R. J. Mathar, Mar 12 2023

A307354 a(n) = Sum_{0<=i<=j<=n} (-1)^(i+j) * (i+j)!/(i!*j!).

Original entry on oeis.org

1, 2, 6, 19, 65, 231, 841, 3110, 11628, 43834, 166298, 634140, 2428336, 9331688, 35967462, 138987715, 538287881, 2088842463, 8119916647, 31613327405, 123251518641, 481125828853, 1880262896537, 7355767408395, 28803717914791, 112887697489907, 442784607413427
Offset: 0

Views

Author

Seiichi Manyama, Apr 03 2019

Keywords

Crossrefs

Partial sums of A026641. - Seiichi Manyama, Jan 30 2023

Programs

  • Mathematica
    Table[Sum[Sum[(-1)^(i + j)*(i + j)!/(i!*j!), {i, 0, j}], {j, 0, n}], {n, 0, 25}] (* Vaclav Kotesovec, Apr 04 2019 *)
  • PARI
    a(n) = sum(i=0, n, sum(j=i, n, (-1)^(i+j)*(i+j)!/(i!*j!)));
    
  • PARI
    a(n) = sum(k=0, n\3, (-1)^k*binomial(2*n-3*k, n)); \\ Seiichi Manyama, Jan 29 2023
    
  • PARI
    my(N=30, x='x+O('x^N)); Vec(1/(sqrt(1-4*x)*(1+x^3*(2/(1+sqrt(1-4*x)))^3))) \\ Seiichi Manyama, Jan 29 2023

Formula

a(n) = (A006134(n) + A120305(n))/2.
From Vaclav Kotesovec, Apr 04 2019: (Start)
Recurrence: 2*n*a(n) = (9*n-4)*a(n-1) - (3*n-2)*a(n-2) - 2*(2*n-1)*a(n-3).
a(n) ~ 2^(2*n+3) / (9*sqrt(Pi*n)). (End)
From Seiichi Manyama, Jan 29 2023: (Start)
a(n) = Sum_{k=0..floor(n/3)} (-1)^k * binomial(2*n-3*k,n).
G.f.: 1 / ( sqrt(1-4*x) * (1 + x^3 * c(x)^3) ), where c(x) is the g.f. of A000108. (End)
a(n) = [x^n] 1/((1+x^3) * (1-x)^(n+1)). - Seiichi Manyama, Apr 08 2024

A360168 a(n) = Sum_{k=0..floor(n/3)} binomial(2*n,n-3*k).

Original entry on oeis.org

1, 2, 6, 21, 78, 297, 1145, 4447, 17358, 68001, 267141, 1051767, 4148281, 16385111, 64797543, 256515731, 1016368078, 4030114641, 15990813773, 63485616391, 252175202373, 1002136689071, 3984080489263, 15844839393411, 63036297959993, 250855287692647
Offset: 0

Views

Author

Seiichi Manyama, Jan 28 2023

Keywords

Crossrefs

Programs

  • Maple
    A360168 := proc(n)
        add(binomial(2*n,n-3*k),k=0..n/3) ;
    end proc:
    seq(A360168(n),n=0..70) ; # R. J. Mathar, Mar 12 2023
  • Mathematica
    a[n_] := Sum[Binomial[2*n, n - 3*k], {k, 0, Floor[n/3]}]; Array[a, 26, 0] (* Amiram Eldar, Jan 28 2023 *)
  • PARI
    a(n) = sum(k=0, n\3, binomial(2*n, n-3*k));
    
  • PARI
    my(N=30, x='x+O('x^N)); Vec(1/(sqrt(1-4*x)*(1-x^3*(2/(1+sqrt(1-4*x)))^6)))

Formula

G.f.: 1 / ( sqrt(1-4*x) * (1 - x^3 * c(x)^6) ), where c(x) is the g.f. of A000108.
D-finite with recurrence n*a(n) +2*(-4*n+3)*a(n-1) +8*(2*n-3)*a(n-2) +3*(-n+2)=0. - R. J. Mathar, Mar 12 2023
a(n) = [x^n] 1/(((1-x)^3-x^3) * (1-x)^(n-2)). - Seiichi Manyama, Apr 10 2024

A371871 a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-3*k-2,n-3*k).

Original entry on oeis.org

1, 0, 1, 5, 18, 66, 246, 924, 3493, 13277, 50697, 194327, 747319, 2882061, 11142027, 43167573, 167561586, 651513594, 2537041938, 9892847952, 38623197264, 150959213886, 590626854072, 2312979822738, 9065733950526, 35561306875380, 139595183125750
Offset: 0

Views

Author

Seiichi Manyama, Apr 10 2024

Keywords

Crossrefs

Programs

  • Maple
    A371871 := proc(n)
        1/(1-x^3)/(1-x)^(n-1) ;
        coeftayl(%,x=0,n) ;
    end proc:
    seq(A371871(n),n=0..60) ; # R. J. Mathar, Apr 22 2024
  • PARI
    a(n) = sum(k=0, n\3, binomial(2*n-3*k-2, n-3*k));

Formula

a(n) = [x^n] 1/((1-x^3) * (1-x)^(n-1)).
D-finite with recurrence 9*n*a(n) +3*(-17*n+16)*a(n-1) +3*(21*n-50)*a(n-2) +(-17*n+16)*a(n-3) +10*(2*n-5)*a(n-4)=0. - R. J. Mathar, Apr 22 2024

A371842 a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-2*k+1,n-3*k).

Original entry on oeis.org

1, 3, 10, 36, 133, 498, 1882, 7161, 27391, 105210, 405499, 1567332, 6072724, 23578221, 91712089, 357301827, 1393986898, 5445422340, 21296030401, 83370591273, 326688422203, 1281227165640, 5028742763407, 19751799462378, 77632592859316, 305316702610581
Offset: 0

Views

Author

Seiichi Manyama, Apr 08 2024

Keywords

Crossrefs

Cf. A105872.

Programs

  • PARI
    a(n) = sum(k=0, n\3, binomial(2*n-2*k+1, n-3*k));

Formula

a(n) = [x^n] 1/((1-x-x^3) * (1-x)^(n+1)).
From Vaclav Kotesovec, Apr 08 2024: (Start)
Recurrence: (n-1)*a(n) = (9*n-11)*a(n-1) - 2*(11*n-16)*a(n-2) + (9*n-13)*a(n-3) - 2*(2*n-3)*a(n-4).
G.f.: 2 / (4*x^2 + 3*x*sqrt(1-4*x) - 9*x + 2).
a(n) ~ 2^(2*n+3) / (3*sqrt(Pi*n)). (End)

A371854 a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-k+2,n-3*k).

Original entry on oeis.org

1, 4, 15, 57, 219, 847, 3290, 12819, 50066, 195909, 767790, 3013002, 11837043, 46548919, 183209125, 721628692, 2844297119, 11217639757, 44265835891, 174765349896, 690308413773, 2727823240762, 10783518961394, 42644560775835, 168699835910561, 667580653569309
Offset: 0

Views

Author

Seiichi Manyama, Apr 09 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n\3, binomial(2*n-k+2, n-3*k));

Formula

a(n) = [x^n] 1/(((1-x)^2-x^3) * (1-x)^(n+1)).
Showing 1-10 of 10 results.