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 1-2 of 2 results.

A212342 Sequence of coefficients of x^0 in marked mesh pattern generating function Q_{n,132}^(0,3,0,0)(x).

Original entry on oeis.org

1, 1, 2, 5, 9, 14, 20, 27, 35, 44, 54, 65, 77, 90, 104, 119, 135, 152, 170, 189, 209, 230, 252, 275, 299, 324, 350, 377, 405, 434, 464, 495, 527, 560, 594, 629, 665, 702, 740, 779, 819, 860, 902, 945, 989, 1034, 1080, 1127, 1175, 1224, 1274, 1325, 1377, 1430, 1484, 1539, 1595, 1652, 1710, 1769, 1829, 1890, 1952, 2015, 2079
Offset: 0

Views

Author

N. J. A. Sloane, May 09 2012

Keywords

Crossrefs

A201163 is similar. - Robert Price, Jun 02 2012

Programs

  • Mathematica
    QQ0[t, x] = (1 - (1-4*x*t)^(1/2)) / (2*x*t); QQ1[t, x] = 1/(1 - t*QQ0[t, x]); QQ2[t, x] = (1 + t*(QQ1[t, x] - QQ0[t, x]))/(1 - t*QQ0[t, x]); QQ3[t, x] = (1 + t*(QQ2[t, x] - QQ0[t, x] + t*(QQ1[t, x] - QQ0[t,  x])))/(1 - t*QQ0[t, x]); q=Simplify[Series[QQ3[t, x], {t, 0, 35}]]; CoefficientList[q /. x -> 0, t] (* Robert Price, Jun 04 2012 *)

Formula

For n>=2, a(n)=(n^2+n-2)/2. - Robert Price, Jun 02 2012
For n>=5, a(n)=3*a(n-1)-3*a(n-2)+a(n-3). G.f.: (1-2*x+2*x^2+x^3-x^4)/(1-x)^3. - Colin Barker, Jul 06 2012

Extensions

a(10)-a(35) from Robert Price, Jun 02 2012
Added a(0) to correspond to given offset and to be consistent with A212346, Robert Price, Jun 02 2012

A212347 Sequence of coefficients of x^1 in marked mesh pattern generating function Q_{n,132}^(0,4,0,0)(x).

Original entry on oeis.org

14, 56, 144, 300, 550, 924, 1456, 2184, 3150, 4400, 5984, 7956, 10374, 13300, 16800, 20944, 25806, 31464, 38000, 45500, 54054, 63756, 74704, 87000, 100750, 116064, 133056, 151844, 172550, 195300, 220224, 247456, 277134, 309400, 344400, 382284, 423206, 467324, 514800, 565800, 620494, 679056, 741664, 808500, 879750, 955604
Offset: 5

Views

Author

N. J. A. Sloane, May 09 2012

Keywords

Programs

  • Mathematica
    QQ0[t, x] = (1 - (1-4*x*t)^(1/2)) / (2*x*t); QQ1[t, x] = 1/(1 - t*QQ0[t, x]); QQ2[t, x] = (1 + t*(QQ1[t, x] - QQ0[t, x]))/(1 - t*QQ0[t, x]); QQ3[t, x] = (1 + t*(QQ2[t, x] - QQ0[t, x] + t*(QQ1[t, x] - QQ0[t, x])))/(1 - t*QQ0[t, x]); QQ4[t, x] = (1 + t*(QQ3[t, x] - QQ0[t, x] + t*(QQ2[t, x] - QQ0[t, x]) + (2*t^2*(QQ1[t, x] - QQ0[t, x]))))/(1 - t*QQ0[t, x]); CoefficientList[Coefficient[Simplify[Series[QQ4[t, x], {t, 0, 35}]],x],t] (* Robert Price, Jun 04 2012 *)
    Table[(n-4)*(n-3)*(n+1)*(n+2)/6, {n, 5, 50}] (* Jean-François Alcover, Sep 21 2017 *)

Formula

For n>=5, a(n)=(n^2-2n-8)(n^2-2n-3)/6 or a(n)=(n-4)*A212346(n-1).
G.f.: -2*x^5*(2*x^2-7*x+7) / (x-1)^5. - Colin Barker, Jul 22 2013

Extensions

a(10)-a(35) from Robert Price, Jun 02 2012
Showing 1-2 of 2 results.