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 21-25 of 25 results.

A011910 a(n) = floor( n*(n-1)*(n-2)/28 ).

Original entry on oeis.org

0, 0, 0, 0, 0, 2, 4, 7, 12, 18, 25, 35, 47, 61, 78, 97, 120, 145, 174, 207, 244, 285, 330, 379, 433, 492, 557, 626, 702, 783, 870, 963, 1062, 1169, 1282, 1402, 1530, 1665, 1807, 1958, 2117, 2284, 2460, 2644, 2838, 3040, 3252, 3474, 3706, 3948, 4200, 4462, 4735, 5019, 5315, 5621, 5940, 6270, 6612, 6966, 7332, 7712, 8104, 8509, 8928, 9360, 9805, 10265, 10739, 11227
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A011886.

Programs

Formula

a(n) = floor(A007531(n)/28). - Wesley Ivan Hurt, Feb 25 2014
G.f.: x^5*(2-2*x+x^2+x^3-x^4+2*x^6-x^7+x^9-x^10+2*x^11-2*x^12+2*x^13+x^19+ x^21-2*x^22+3*x^23-2*x^24+x^25)/((1-x)^4*(1+x)*(1+x^2)*(1-x+x^2-x^3+x^4-x^5+x^6)*(1+x+x^2+x^3+x^4+x^5+x^6)*(1-x^2+x^4-x^6+x^8-x^10+x^12)). - Peter J. C. Moses, Jun 02 2014

A011911 a(n) = floor( n*(n-1)*(n-2)/29 ).

Original entry on oeis.org

0, 0, 0, 0, 0, 2, 4, 7, 11, 17, 24, 34, 45, 59, 75, 94, 115, 140, 168, 200, 235, 275, 318, 366, 418, 475, 537, 605, 677, 756, 840, 930, 1026, 1128, 1238, 1354, 1477, 1607, 1745, 1890, 2044, 2205, 2375, 2553, 2740, 2935, 3140, 3354, 3578, 3811, 4055, 4308, 4572, 4846, 5131, 5427, 5735, 6053, 6384, 6726, 7080, 7446, 7824, 8216, 8620, 9037, 9467, 9911, 10368, 10840
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A011886.

Programs

  • Magma
    [Floor(6*Binomial(n,3)/29): n in [0..80]]; // G. C. Greubel, Oct 19 2024
    
  • Mathematica
    Floor[6*Binomial[Range[0,75], 3]/29] (* G. C. Greubel, Oct 19 2024 *)
    Table[Floor[(2n-3n^2+n^3)/29],{n,0,100}] (* Harvey P. Dale, Jan 25 2025 *)
  • SageMath
    [6*binomial(n,3)//29 for n in range(81)] # G. C. Greubel, Oct 19 2024

Formula

G.f.: x^5*(2+x*(-2+x+x^3-x^4+2*x^5-2*x^6+2*x^7-x^8+x^9-x^10+2*x^11-x^12+x^13-x^14+2*x^15-2*x^16+2*x^17-x^18+x^19+x^21-2*x^22+3*x^23-2*x^24+x^25))/((1-x)^3*(1-x^29)). - Peter J. C. Moses, Jun 02 2014

Extensions

More terms added by G. C. Greubel, Oct 19 2024

A011912 a(n) = floor(n*(n-1)*(n-2)/30).

Original entry on oeis.org

0, 0, 0, 0, 0, 2, 4, 7, 11, 16, 24, 33, 44, 57, 72, 91, 112, 136, 163, 193, 228, 266, 308, 354, 404, 460, 520, 585, 655, 730, 812, 899, 992, 1091, 1196, 1309, 1428, 1554, 1687, 1827, 1976, 2132, 2296, 2468, 2648, 2838, 3036, 3243, 3459, 3684, 3920, 4165, 4420, 4685, 4960, 5247, 5544, 5852, 6171, 6501, 6844, 7198, 7564, 7942, 8332, 8736, 9152, 9581, 10023, 10478, 10948
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A011886.

Programs

  • Magma
    [Floor(n*(n-1)*(n-2)/30): n in [0..80]]; // Vincenzo Librandi, Jul 07 2012
    
  • Maple
    seq(floor(binomial(n,3)/5), n=0..80); # Zerinvary Lajos, Jan 12 2009
  • Mathematica
    Table[Floor[(n(n-1)(n-2))/30],{n,0,80}] (* or *) LinearRecurrence[{3,-3,1,0, 1,-3,3,-1},{0,0,0,0,0,2,4,7},81] (* Harvey P. Dale, Jun 20 2011 *)
    CoefficientList[Series[x^5*(x^2-2*x+2)/((-1+x)^4*(x^4+x^3+x^2+x+1)),{x,0,80}],x] (* Vincenzo Librandi, Jul 07 2012 *)
  • SageMath
    [binomial(n,3)//5 for n in range(81)] # G. C. Greubel, Oct 19 2024

Formula

From R. J. Mathar, Apr 15 2010: (Start)
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) + a(n-5) - 3*a(n-6) + 3*a(n-7) - a(n-8).
G.f.: x^5*(2-2*x+x^2) / ( (1-x)^4*(1+x+x^2+x^3+x^4) ). (End)

A011913 a(n) = floor(n*(n - 1)*(n - 2)/31).

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 3, 6, 10, 16, 23, 31, 42, 55, 70, 88, 108, 131, 157, 187, 220, 257, 298, 342, 391, 445, 503, 566, 634, 707, 785, 870, 960, 1056, 1158, 1266, 1381, 1503, 1632, 1768, 1912, 2063, 2221, 2388, 2563, 2746, 2938, 3138, 3347, 3565, 3793, 4030, 4277, 4534, 4800, 5077, 5365, 5663, 5972, 6292, 6623, 6965, 7320, 7686, 8064, 8454, 8856, 9271, 9699, 10140, 10594
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A011886.

Programs

  • Magma
    [Floor(6*Binomial(n,3)/31): n in [0..80]]; // G. C. Greubel, Oct 19 2024
    
  • Mathematica
    Floor[6*Binomial[Range[0,80], 3]/31] (* G. C. Greubel, Oct 19 2024 *)
  • PARI
    a(n) = n*(n-1)*(n-2)\31 \\ Jianing Song, Oct 15 2018
    
  • SageMath
    [6*binomial(n,3)//31 for n in range(81)] # G. C. Greubel, Oct 19 2024

Formula

G.f.: x^5*(1 +x^4 -x^5 +2*x^7 -x^8 +x^10 -x^11 +x^12 +x^14 -x^15 +x^16 -x^18 +2*x^19 -x^21 +x^22 +2*x^26 -2*x^27 +x^28)/((1-x)^3*(1-x^31)). - Peter J. C. Moses, Jun 02 2014

Extensions

More terms added by G. C. Greubel, Oct 19 2024

A011914 a(n) = floor(n*(n - 1)*(n - 2)/32).

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 3, 6, 10, 15, 22, 30, 41, 53, 68, 85, 105, 127, 153, 181, 213, 249, 288, 332, 379, 431, 487, 548, 614, 685, 761, 842, 930, 1023, 1122, 1227, 1338, 1456, 1581, 1713, 1852, 1998, 2152, 2313, 2483, 2660, 2846, 3040, 3243, 3454, 3675, 3904, 4143, 4392, 4650, 4919, 5197, 5486, 5785, 6095, 6416, 6748, 7091, 7445, 7812, 8190
Offset: 0

Views

Author

N. J. A. Sloane, Dec 11 1996

Keywords

Crossrefs

Cf. A011886.

Programs

Formula

G.f.: x^5*(1-x+x^2)*(1 +x -x^3 -x^4 +x^5 +x^6 +2*x^7 -x^8 -x^9 -x^10 +x^11 +x^12 +2*x^13 -x^14 -x^15 +2*x^18 -x^21 +x^23 +x^24 -x^26 +x^27)/((1-x)^4*(1 +x)*(1+x^2)*(1+x^4)*(1+x^8)*(1+x^16)). - Peter J. C. Moses, Jun 02 2014

Extensions

More terms added by G. C. Greubel, Oct 20 2024
Previous Showing 21-25 of 25 results.