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 1-5 of 5 results.

A290761 Irregular triangle, read by rows, of coefficients of polynomials that are the "nonstandard" factor of polynomials yielding the columns (up to sign) of triangle A290053, beginning with column 3.

Original entry on oeis.org

3, 5, -6, 16, 1, 7, 16, 28, 0, 15, 225, 1265, 3707, 7120, 4900, -6480, 27648, 3, 83, 961, 6201, 24708, 60700, 87968, 85056, 0, 63, 2457, 41580, 404866, 2532971, 10651177, 30102338, 56577724, 72856616, 36562176, -51101568, 298598400, 9, 531, 14010, 219106
Offset: 1

Views

Author

Gregory Gerard Wojnar, Aug 09 2017

Keywords

Comments

The polynomials come in pairs: first of odd degree; second of even degree 1 greater, whose constant term is always zero. Observations: All coefficients are positive except for the linear coefficients of the first polynomial in each pair, which are always negative. From the first of one pair to the first of the next pair, the degree always grows by 4. The "standard" factors of polynomials yielding the columns of triangle A290053 (beginning with column 3) are always of the form (1/A053657(k+2))*(N + k + 2) in odd rows of this triangle A290761, and of the form (N/A053657(k+2))*(N + k + 3)^2 in even rows of this triangle, where k is the row number. See examples.

Examples

			The first rows of the triangle are parsed as follows:
3, 5, -6, 16;
1, 7, 16, 28, 0;
15, 225, 1265, 3707, 7120, 4900, -6480, 27648;
3, 83, 961, 6201, 24708, 60700, 87968, 85056, 0;
63, 2457, 41580, 404866, 2532971, 10651177, 30102338, 56577724, 72856616, 36562176, -51101568, 298598400;
9, 531, 14010, 219106, 2266137, 16325259, 83797380, 307998768, 802828704, 1433652560, 1651979520, 1239918336, 0.
The associated full polynomials giving the columns of triangle A290053 are then:
(1/24) * (N + 3) * (3*N^3 + 5*N^2 - 6*N + 16);
(N/48) * (N + 5)^2 * (1*N^3 + 7*N^2 + 16*N + 28);
(1/5760) * (N + 5) * (15*N^7 + 225*N^6 + 1265*N^5 + 3707*N^4 + 7120*N^3 + 4900*N^2 - 6480*N + 27648);
(N/11520) * (N + 7)^2 * (3*N^7 + 83*N^6 + 961*N^5 + 6201*N^4 + 24708*N^3 + 60700*N^2 + 87968*N + 85056); etc.
		

Crossrefs

The first column of this triangle is A290030; alternating entries of the first column give A260326. See also triangle A290053, whose columns are A000012-A000096, A290061-A290071, A290127-A290723, etc.

A290061 a(n) = (1/24)*(n + 3)*(3*n^3 + 5*n^2 - 6*n + 16).

Original entry on oeis.org

3, 10, 31, 77, 162, 303, 520, 836, 1277, 1872, 2653, 3655, 4916, 6477, 8382, 10678, 13415, 16646, 20427, 24817, 29878, 35675, 42276, 49752, 58177, 67628, 78185, 89931, 102952, 117337, 133178, 150570, 169611, 190402, 213047, 237653, 264330, 293191, 324352, 357932
Offset: 1

Views

Author

Gregory Gerard Wojnar, Jul 19 2017

Keywords

Crossrefs

Column 3 of A290053.

Programs

  • Mathematica
    Table[(1/24)(n+3)(3n^3+5n^2-6n+16),{n,40}] (* or *) LinearRecurrence[{5,-10,10,-5,1},{3,10,31,77,162},40] (* Harvey P. Dale, Oct 29 2018 *)
  • PARI
    Vec(x*(3 - 5*x + 11*x^2 - 8*x^3 + 2*x^4) / (1 - x)^5 + O(x^50)) \\ Colin Barker, Jul 20 2017
    
  • PARI
    vector(50,n,(n+3)*(3*n^3+5*n^2-6*n+16)/24) \\ Derek Orr, Jul 24 2017

Formula

From Colin Barker, Jul 20 2017: (Start)
G.f.: x*(3 - 5*x + 11*x^2 - 8*x^3 + 2*x^4) / (1 - x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n > 4.
(End)

A290071 a(n) = (1/48)*n*(n+5)^2*(1*n^3 + 7*n^2 + 16*n + 28).

Original entry on oeis.org

0, 39, 196, 664, 1809, 4250, 8954, 17346, 31434, 53949, 88500, 139744, 213571, 317304, 459914, 652250, 907284, 1240371, 1669524, 2215704, 2903125, 3759574, 4816746, 6110594, 7681694, 9575625, 11843364, 14541696, 17733639, 21488884, 25884250, 31004154, 36941096
Offset: 0

Views

Author

Gregory Gerard Wojnar, Jul 19 2017

Keywords

Crossrefs

This is the negation of column 4 in triangle A290053.

Programs

  • Mathematica
    LinearRecurrence[{7,-21,35,-35,21,-7,1},{0,39,196,664,1809,4250,8954},40] (* Harvey P. Dale, Nov 15 2022 *)
  • PARI
    concat(0, Vec(x*(39 - 77*x + 111*x^2 - 88*x^3 + 36*x^4 - 6*x^5) / (1 - x)^7 + O(x^50))) \\ Colin Barker, Jul 20 2017
    
  • PARI
    vector(50,n,n*(n+5)^2*(n^3+7*n^2+16*n+28)/48) \\ Derek Orr, Jul 24 2017

Formula

From Colin Barker, Jul 20 2017: (Start)
G.f.: x*(39 - 77*x + 111*x^2 - 88*x^3 + 36*x^4 - 6*x^5) / (1 - x)^7.
a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n > 6.
(End)

A290127 a(n) = (1/5760)*(n + 5)*(15*n^7 + 225*n^6 + 1265*n^5 + 3707*n^4 + 7120*n^3 + 4900*n^2 - 6480*n + 27648).

Original entry on oeis.org

40, 252, 1457, 6168, 20773, 59279, 149271, 340821, 719187, 1422247, 2663718, 4763315, 8185110, 13585456, 21871946, 34274982, 52433634, 78497574, 115246975, 166232370, 235936571, 329960853, 455237713, 620272619, 835417269, 1113176985, 1468554972, 1919436277
Offset: 1

Views

Author

Gregory Gerard Wojnar, Jul 20 2017

Keywords

Crossrefs

This is column 5 of triangle A290053.

Programs

  • Mathematica
    LinearRecurrence[{9,-36,84,-126,126,-84,36,-9,1},{40,252,1457,6168,20773,59279,149271,340821,719187},30] (* Harvey P. Dale, Jul 17 2024 *)
  • PARI
    Vec(x*(40 - 108*x + 629*x^2 - 1233*x^3 + 1585*x^4 - 1306*x^5 + 666*x^6 - 192*x^7 + 24*x^8) / (1 - x)^9 + O(x^30)) \\ Colin Barker, Aug 09 2017

Formula

G.f.: x*(40 - 108*x + 629*x^2 - 1233*x^3 + 1585*x^4 - 1306*x^5 + 666*x^6 - 192*x^7 + 24*x^8) / (1 - x)^9. - Colin Barker, Aug 09 2017

A290723 a(n) = (1/11520) * n*(n+7)^2 * (3*n^7 + 83*n^6 + 961*n^5 + 6201*n^4 + 24708*n^3 + 60700*n^2 + 87968*n + 85056).

Original entry on oeis.org

0, 1476, 11772, 61595, 249986, 846306, 2495961, 6601035, 15978570, 35938992, 75976077, 152318826, 291665618, 536502980, 952506198, 1638627738, 2740602996, 4468742196, 7121033250, 11112754029, 17013984714, 25596622646, 37892734319, 55266332805, 79500944910
Offset: 0

Views

Author

Gregory Gerard Wojnar, Aug 09 2017

Keywords

Crossrefs

This is the negation of column 6 of triangle A290053.

Programs

  • Mathematica
    CoefficientList[Series[x (1476 - 4464 x + 13283 x^2 - 23639 x^3 + 28885 x^4 - 24502 x^5 + 14202 x^6 - 5376 x^7 + 1200 x^8 - 120 x^9)/(1 - x)^11, {x, 0, 24}], x] (* Michael De Vlieger, Aug 09 2017 *)
  • PARI
    concat(0, Vec(x*(1476 - 4464*x + 13283*x^2 - 23639*x^3 + 28885*x^4 - 24502*x^5 + 14202*x^6 - 5376*x^7 + 1200*x^8 - 120*x^9) / (1 - x)^11 + O(x^30))) \\ Colin Barker, Aug 09 2017

Formula

G.f.: x*(1476 - 4464*x + 13283*x^2 - 23639*x^3 + 28885*x^4 - 24502*x^5 + 14202*x^6 - 5376*x^7 + 1200*x^8 - 120*x^9) / (1 - x)^11. - Colin Barker, Aug 09 2017
Showing 1-5 of 5 results.