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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A008383 Coordination sequence for A_4 lattice.

Original entry on oeis.org

1, 20, 110, 340, 780, 1500, 2570, 4060, 6040, 8580, 11750, 15620, 20260, 25740, 32130, 39500, 47920, 57460, 68190, 80180, 93500, 108220, 124410, 142140, 161480, 182500, 205270, 229860, 256340, 284780, 315250, 347820, 382560, 419540, 458830, 500500, 544620
Offset: 0

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Author

Keywords

References

  • M. O'Keeffe, Coordination sequences for lattices, Zeit. f. Krist., 210 (1995), 905-908.

Crossrefs

Programs

  • Magma
    [n eq 0 select 1 else 5*n*(7*n^2+5)/3: n in [0..45]]; // G. C. Greubel, May 25 2023
    
  • Maple
    a:= n-> `if`(n=0, 1, 35/3*n^3+25/3*n): seq (a(n), n=0..50);
  • Mathematica
    CoefficientList[Series[(1+16x+36x^2+16x^3+x^4)/(1-x)^4,{x,0,40}],x] (* Harvey P. Dale, Dec 01 2013 *)
    Join[{1}, LinearRecurrence[{4, -6, 4, -1}, {20, 110, 340, 780}, 40]] (* Jean-François Alcover, Jan 07 2019 *)
  • SageMath
    [5*n*(7*n^2+5)/3+int(n==0) for n in range(46)] # G. C. Greubel, May 25 2023

Formula

a(n) = 5*n*(7*n^2 + 5)/3, a(0) = 1.
G.f.: (1+16*x+36*x^2+16*x^3+x^4)/(1-x)^4 = 1+10*x*(2+3*x+2*x^2)/(x-1)^4. - Colin Barker, Apr 13 2012
E.g.f.: (1/3)*(3 + 5*x*(12 + 21*x + 7*x^2)*exp(x)). - G. C. Greubel, May 25 2023

A008385 Coordination sequence for A_5 lattice.

Original entry on oeis.org

1, 30, 240, 1010, 2970, 7002, 14240, 26070, 44130, 70310, 106752, 155850, 220250, 302850, 406800, 535502, 692610, 882030, 1107920, 1374690, 1687002, 2049770, 2468160, 2947590, 3493730, 4112502, 4810080, 5592890, 6467610, 7441170, 8520752
Offset: 0

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Author

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Programs

  • Magma
    [n eq 0 select 1 else (21*n^4 +35*n^2 +4)/2: n in [0..50]]; // G. C. Greubel, May 26 2023
    
  • Maple
    1, seq((21*n^4 +35*n^2 +4)/2, n=1..50);
  • Mathematica
    Table[n^2*(21*n^2 +35)/2 +2 -Boole[n==0], {n,0,50}] (* G. C. Greubel, May 26 2023 *)
  • Maxima
    A008385[n]:=21/2*n^4+35/2*n^2+2$
    makelist(A008385[n],n,0,30); /* Martin Ettl, Oct 26 2012 */
    
  • SageMath
    [n^2*(21*n^2 +35)/2 +2 -int(n==0) for n in range(51)] # G. C. Greubel, May 26 2023

Formula

a(n) = (21*n^4 + 35*n^2 + 4)/2, a(0) = 1.
G.f.: (1+x)*(1+24*x+76*x^2+24*x^3+x^4)/(1-x)^5. - Colin Barker, Apr 13 2012
E.g.f.: (1/2)*(-2 + (4 + 56*x + 182*x^2 + 126*x^3 + 21*x^4)*exp(x)). - G. C. Greubel, May 26 2023

A008531 Coordination sequence for {A_4}* lattice.

Original entry on oeis.org

1, 10, 50, 150, 340, 650, 1110, 1750, 2600, 3690, 5050, 6710, 8700, 11050, 13790, 16950, 20560, 24650, 29250, 34390, 40100, 46410, 53350, 60950, 69240, 78250, 88010, 98550, 109900, 122090, 135150, 149110, 164000, 179850, 196690, 214550, 233460, 253450
Offset: 0

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Keywords

Comments

Coordination sequence for 4-dimensional cyclotomic lattice Z[zeta_10].

References

  • M. O'Keeffe, Coordination sequences for lattices, Zeit. f. Krist., 210 (1995), 905-908.

Crossrefs

Cf. A222408.

Programs

  • GAP
    Concatenation([1], List([1..45], n-> 5*n*(1+n^2))); # G. C. Greubel, Nov 10 2019
  • Magma
    [1] cat [5*n*(1+n^2): n in [1..45]]; // G. C. Greubel, Nov 10 2019
    
  • Maple
    1, seq( 5*k^3+5*k, k=1..40);
  • Mathematica
    CoefficientList[Series[(1 +6x +16x^2 +6x^3 +x^4)/(1-x)^4, {x, 0, 50}], x] (* Vincenzo Librandi, Oct 15 2013 *)
    LinearRecurrence[{4,-6,4,-1},{1,10,50,150,340},40] (* Harvey P. Dale, Jun 09 2016 *)
  • PARI
    a(n)=5*n*(n^2+1) \\ Charles R Greathouse IV, Mar 08 2013
    
  • Sage
    [1]+[5*n*(1+n^2) for n in (1..45)] # G. C. Greubel, Nov 10 2019
    

Formula

G.f.: (1 +6*x +16*x^2 +6*x^3 +x^4)/(1-x)^4. - Colin Barker, Sep 21 2012
E.g.f.: 1 + x*(10 + 15*x + 5*x^2)*exp(x). - G. C. Greubel, Nov 10 2019

A008349 Crystal ball sequence for E_8 lattice.

Original entry on oeis.org

1, 241, 9361, 131041, 996001, 5109841, 20015281, 64495681, 179375041, 444798001, 1006201681, 2111519521, 4162485601, 7783236241, 13909734001, 23903867521, 39696408961, 63963339121, 100340378641, 153680892001
Offset: 0

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Author

Keywords

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Programs

  • Magma
    [57/7*n^8 + 108/7*n^7 + 30*n^6 + 72*n^5 + 39*n^4 + 36*n^3 + 300/7*n^2 - 24/7*n + 1: n in [0..40]]; // Vincenzo Librandi, Dec 16 2015
    
  • Maple
    57/7*n^8+108/7*n^7+30*n^6+72*n^5+39*n^4+36*n^3+300/7*n^2-24/7*n+1;
  • Mathematica
    CoefficientList[Series[(1+232x+7228x^2+107224x^5+133510x^4+ 55384x^3+ 24508x^6+ 232x^7+ x^8)/(1-x)^9,{x,0,30}],x] (* or *) LinearRecurrence[ {9,-36,84,-126,126,-84,36,-9,1},{1,241,9361,131041,996001,5109841,20015281,64495681,179375041},30] (* Harvey P. Dale, Jun 12 2012 *)
  • PARI
    a(n)=(57*n^8 + 108*n^7 + 210*n^6 + 504*n^5 + 273*n^4 + 252*n^3 + 300*n^2 - 24*n + 7)/7 \\ Charles R Greathouse IV, Feb 10 2017
  • Python
    A008349_list, m = [], [328320, -1071360, 1347840, -812160, 233280, -25920, 240, 0, 1]
    for _ in range(10**2):
        A008349_list.append(m[-1])
        for i in range(8):
            m[i+1] += m[i] # Chai Wah Wu, Dec 15 2015
    

Formula

G.f.: (1 + 232*x + 7228*x^2 + 55384*x^3 + 133510*x^4 + 107224*x^5 + 24508*x^6 + 232*x^7 + x^8)/(1 - x)^9.
a(0)=1, a(1)=241, a(2)=9361, a(3)=131041, a(4)=996001, a(5)=5109841, a(6)=20015281, a(7)=64495681, a(8)=179375041, a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9). - Harvey P. Dale, Jun 12 2012

Extensions

The values given by O'Keeffe are incorrect.

A008387 Coordination sequence for A_6 lattice.

Original entry on oeis.org

1, 42, 462, 2562, 9492, 27174, 65226, 137886, 264936, 472626, 794598, 1272810, 1958460, 2912910, 4208610, 5930022, 8174544, 11053434, 14692734, 19234194, 24836196, 31674678, 39944058, 49858158, 61651128, 75578370, 91917462, 110969082
Offset: 0

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Author

Keywords

Crossrefs

Row 6 of A103881.

Programs

  • Magma
    [n eq 0 select 1 else 7*n*(11*n^4+35*n^2+14)/10: n in [0..50]]; // G. C. Greubel, May 26 2023
    
  • Maple
    1, seq(7*n*(11*n^4+35*n^2+14)/10, n=1..40);
  • Mathematica
    LinearRecurrence[{6,-15,20,-15,6,-1}, {1,42,462,2562,9492,27174,65226}, 30] (* Jean-François Alcover, Jan 07 2019 *)
  • SageMath
    [7*n*(11*n^4 +35*n^2 +14)/10 +int(n==0) for n in range(51)] # G. C. Greubel, May 26 2023

Formula

a(n) = S(n,6) = 7*n*(11*n^4 + 35*n^2 + 14)/10, with S(n,m) = Sum_{k=0..m} binomial(m,k)^2 * binomial(n-k+m-1, m-1), for n > 0, and a(0) = 1.
G.f.: (1+36*x+225*x^2+400*x^3+225*x^4+36*x^5+x^6)/(1-x)^6 = 1 + 42*x*(1+5*x+10*x^2+5*x^3+x^4)/(1-x)^6. - Colin Barker, Sep 26 2012
E.g.f.: 1 + (1/10)*x*(420 + 1890*x + 2170*x^2 + 770*x^3 + 77*x^4)*exp(x). - G. C. Greubel, May 26 2023

A008528 Coordination sequence for 4-dimensional RR-centered di-isohexagonal orthogonal lattice.

Original entry on oeis.org

1, 18, 102, 318, 732, 1410, 2418, 3822, 5688, 8082, 11070, 14718, 19092, 24258, 30282, 37230, 45168, 54162, 64278, 75582, 88140, 102018, 117282, 133998, 152232, 172050, 193518, 216702, 241668, 268482, 297210, 327918, 360672, 395538, 432582, 471870, 513468, 557442, 603858, 652782, 704280
Offset: 0

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Author

Keywords

References

  • M. O'Keeffe, Coordination sequences for lattices, Zeit. f. Krist., 210 (1995), 905-908.

Programs

  • GAP
    Concatenation([1], List([1..45], n-> n*(7+11*n^2) )); # G. C. Greubel, Nov 09 2019
  • Magma
    I:=[1, 18, 102, 318,732]; [n le 5 select I[n] else 4*Self(n-1) -6*Self(n-2)+4*Self(n-3)-Self(n-4): n in [1..45]]; // Vincenzo Librandi, Jun 19 2012
    
  • Maple
    1, seq(11*k^3+7*k, k=1..45);
  • Mathematica
    CoefficientList[Series[1+6*x*(3+5*x+3*x^2)/(1-x)^4,{x,0,45}],x] (* Vincenzo Librandi, Jun 19 2012 *)
    LinearRecurrence[{4,-6,4,-1},{1,18,102,318,732},45] (* Harvey P. Dale, Apr 27 2017 *)
  • PARI
    vector(46, n, if(n==1,1,(n-1)*(7+11*(n-1)^2)) ) \\ G. C. Greubel, Nov 09 2019
    
  • Sage
    [1]+[n*(7+11*n^2) for n in (1..45)] # G. C. Greubel, Nov 09 2019
    

Formula

a(n) = n*(11*n^2 + 7) with n>0, with a(0)=1.
G.f.: 1 + 6*x*(3 + 5*x + 3*x^2)/(1-x)^4. - R. J. Mathar, Sep 04 2011
E.g.f.: 1 + x*(18 + 33*x + 11*x^2)*exp(x). - G. C. Greubel, Nov 09 2019

A108100 a(n) = (2*n-1)^2 + (2*n+1)^2.

Original entry on oeis.org

2, 10, 34, 74, 130, 202, 290, 394, 514, 650, 802, 970, 1154, 1354, 1570, 1802, 2050, 2314, 2594, 2890, 3202, 3530, 3874, 4234, 4610, 5002, 5410, 5834, 6274, 6730, 7202, 7690, 8194, 8714, 9250, 9802, 10370, 10954, 11554, 12170, 12802, 13450, 14114, 14794, 15490
Offset: 0

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Author

Dorthe Roel (dorthe_roel(AT)hotmail.com or dorthe.roel1(AT)skolekom.dk), Jun 07 2005

Keywords

Crossrefs

Apart from leading term, same as A008527.

Programs

Formula

From R. J. Mathar, Aug 24 2008: (Start)
O.g.f.: 2*(1 + 2*x + 5*x^2)/(1-x)^3.
a(n) = 2*A053755(n). (End)
a(n) = a(-n); a(n) + a(-n) = A158444(n). - Bruno Berselli, Sep 06 2011
a(n) = 2*(A000466(n) + 2). - Martin Ettl, Nov 12 2012
From Elmo R. Oliveira, Nov 16 2024: (Start)
E.g.f.: 2*exp(x)*(1 + 4*x + 4*x^2).
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 2. (End)

A001386 Coordination sequence for 4-dimensional I-centered tetragonal orthogonal lattice.

Original entry on oeis.org

1, 12, 56, 164, 368, 700, 1192, 1876, 2784, 3948, 5400, 7172, 9296, 11804, 14728, 18100, 21952, 26316, 31224, 36708, 42800, 49532, 56936, 65044, 73888, 83500, 93912, 105156, 117264, 130268, 144200, 159092, 174976, 191884, 209848, 228900, 249072, 270396, 292904
Offset: 0

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Author

Keywords

Examples

			G.f.: (1+x)^2*(1+6*x+x^2)/(1-x)^4. - _Colin Barker_, Apr 14 2012
		

References

  • M. O'Keeffe, Coordination sequences for lattices, Zeit. f. Krist., 210 (1995), 905-908.

Crossrefs

Equals 4 * A004006(2n), n>0.

Programs

  • Maple
    [ seq( (16*k^3+20*k)/3, k=1..40) ];
  • Mathematica
    CoefficientList[Series[(1+x)^2*(1+6*x+x^2)/(1-x)^4,{x,0,30}],x] (* Vincenzo Librandi, Apr 15 2012 *)

A008355 Coordination sequence for D_5 lattice.

Original entry on oeis.org

1, 40, 370, 1640, 4930, 11752, 24050, 44200, 75010, 119720, 182002, 265960, 376130, 517480, 695410, 915752, 1184770, 1509160, 1896050, 2353000, 2888002, 3509480, 4226290, 5047720, 5983490, 7043752
Offset: 0

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Crossrefs

A row of array A103903.

Programs

  • Magma
    [1]cat[2*(9*n^2+1)*(n^2+1): n in [1..30]]; // Vincenzo Librandi, Apr 16 2012
  • Maple
    2*(9*n^2+1)*(n^2+1);
  • Mathematica
    CoefficientList[Series[(1+x)*(1+34*x+146*x^2+34*x^3+x^4)/(1-x)^5,{x,0,30}],x] (* Vincenzo Librandi, Apr 16 2012 *)

Formula

a(n) = 2*(9*n^2+1)*(n^2+1) (see MAPLE line).
G.f.: (1+x)*(1+34*x+146*x^2+34*x^3+x^4)/(1-x)^5. [Colin Barker, Apr 14 2012]

A008357 Coordination sequence for D_6 lattice.

Original entry on oeis.org

1, 60, 792, 4724, 18096, 52716, 127816, 271908, 524640, 938652, 1581432, 2537172, 3908624, 5818956, 8413608, 11862148, 16360128, 22130940, 29427672, 38534964, 49770864, 63488684, 80078856
Offset: 0

Views

Author

Keywords

Crossrefs

A row of array A103903.

Programs

  • Maple
    4/15*n*(37+130*n^2+58*n^4);

Formula

G.f.: (x^6+54*x^5+447*x^4+852*x^3+447*x^2+54*x+1)/(x-1)^6. [Colin Barker, Sep 26 2012]
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