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 1-8 of 8 results.

A145153 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where sequence a_k of column k is the expansion of x/((1 - x - x^4)*(1 - x)^(k - 1)).

Original entry on oeis.org

0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 2, 1, 0, 0, 1, 3, 3, 1, 1, 0, 1, 4, 6, 4, 2, 1, 0, 1, 5, 10, 10, 6, 3, 1, 0, 1, 6, 15, 20, 16, 9, 4, 1, 0, 1, 7, 21, 35, 36, 25, 13, 5, 2, 0, 1, 8, 28, 56, 71, 61, 38, 18, 7, 3, 0, 1, 9, 36, 84, 127, 132, 99, 56, 25, 10, 4, 0, 1, 10, 45, 120, 211, 259, 231, 155, 81, 35, 14, 5
Offset: 0

Views

Author

Alois P. Heinz, Oct 03 2008

Keywords

Comments

Each row sequence a_n (for n > 0) is produced by a polynomial of degree n-1, whose (rational) coefficients are given in row n of A145140/A145141. The coefficients *(n-1)! are given in A145142.
Each column sequence a_k is produced by a recursion, whose coefficients are given by row k of A145152.

Examples

			Square array A(n,k) begins:
  0, 0, 0,  0,  0,  0,   0, ...
  1, 1, 1,  1,  1,  1,   1, ...
  0, 1, 2,  3,  4,  5,   6, ...
  0, 1, 3,  6, 10, 15,  21, ...
  0, 1, 4, 10, 20, 35,  56, ...
  1, 2, 6, 16, 36, 71, 127, ...
		

Crossrefs

Columns 0-9 give: A017898(n-1) for n>0, A003269, A098578, A145131, A145132, A145133, A145134, A145135, A145136, A145137.
Main diagonal gives: A145138.
Antidiaginal sums give: A145139.
Numerators/denominators of polynomials for rows give: A145140/A145141.

Programs

  • Maple
    A:= proc(n, k) coeftayl (x/ (1-x-x^4)/ (1-x)^(k-1), x=0, n) end:
    seq(seq(A(n, d-n), n=0..d), d=0..13);
  • Mathematica
    a[n_, k_] := SeriesCoefficient[x/(1 - x - x^4)/(1 - x)^(k - 1), {x, 0, n}]; Table[a[n - k, k], {n, 0, 12}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Dec 05 2013 *)

Formula

G.f. of column k: x/((1-x-x^4)*(1-x)^(k-1)).

A145142 Triangle T(n,k), n>=1, 0<=k<=n-1, read by rows: T(n,k)/(n-1)! is the coefficient of x^k in polynomial p_n for the n-th row sequence of A145153.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 2, 3, 1, 24, 6, 11, 6, 1, 120, 144, 50, 35, 10, 1, 720, 1200, 634, 225, 85, 15, 1, 5040, 9960, 6804, 2464, 735, 175, 21, 1, 80640, 89040, 71868, 29932, 8449, 1960, 322, 28, 1, 1088640, 1231776, 789984, 375164, 112644, 25473, 4536, 546, 36, 1
Offset: 1

Views

Author

Alois P. Heinz, Oct 03 2008

Keywords

Examples

			Triangle begins:
    1;
    0,   1;
    0,   1,   1;
    0,   2,   3,   1;
   24,   6,  11,   6,   1;
  120, 144,  50,  35,  10,  1;
		

Crossrefs

T(n,k)/(n-1)! gives: A145140 / A145141.
Diagonal and lower diagonals 1-3 give: A000012, A000217, A000914, A001303.
Row sums are in A052593.

Programs

  • Maple
    row:= proc(n) option remember; local f,i,x; f:= unapply(simplify(sum('cat(a||i) *x^i', 'i'=0..n-1) ), x); unapply(subs(solve({seq(f(i+1)= coeftayl(x/ (1-x-x^4)/ (1-x)^i, x=0, n), i=0..n-1)}, {seq(cat(a||i), i=0..n-1)}), sum('cat(a||i) *x^i', 'i'=0..n-1) ), x); end: T:= (n,k)-> `if`(k<0 or k>=n,0, coeff(row(n)(x),x,k)*(n-1)!): seq(seq(T(n,k), k=0..n-1), n=1..12);
  • Mathematica
    row[n_] := Module[{f, eq}, f = Function[x, Sum[a[k]*x^k, {k, 0, n-1}]]; eq = Table[f[k+1] == SeriesCoefficient[x/(1-x-x^4)/(1-x)^k, {x, 0, n}], {k, 0, n-1}]; Table[a[k], {k, 0, n-1}] /. Solve[eq] // First]; Table[row[n]*(n-1)!, {n, 1, 12}] // Flatten (* Jean-François Alcover, Feb 04 2014, after Alois P. Heinz *)

Formula

See program.

A145126 a(n) = 1 + (6 + (11 + (6 + n)*n)*n)*n/24.

Original entry on oeis.org

1, 2, 6, 16, 36, 71, 127, 211, 331, 496, 716, 1002, 1366, 1821, 2381, 3061, 3877, 4846, 5986, 7316, 8856, 10627, 12651, 14951, 17551, 20476, 23752, 27406, 31466, 35961, 40921, 46377, 52361, 58906, 66046, 73816, 82252, 91391, 101271, 111931, 123411, 135752
Offset: 0

Views

Author

Alois P. Heinz, Oct 03 2008

Keywords

Comments

From Gary W. Adamson, Jul 31 2010: (Start)
Equals (1, 2, 3, 4, 5, ...) convolved with (1, 0, 3, 6, 10, 15, ...).
Example: a(4) = 36 = (5, 4, 3, 2, 1) dot (1, 0, 3, 6, 10) = (5 + 0 + 9 + 12 + 10). (End)
Also the number of permutations of length n that can be sorted by a single block interchange (in the sense of Christie). - Vincent Vatter, Aug 21 2013

Crossrefs

5th row of A145153. See row 5 of A145140/A145141 for rational coefficients and A145142 for 24 * coefficients of polynomial.

Programs

  • Maple
    a:= n-> 1+ (6+ (11+ (6+ n) *n) *n) *n/24: seq(a(n), n=0..40);
    # second Maple program:
    with(combinat): seq(binomial(n+3, 4)+1, n=0..40); # Zerinvary Lajos, Mar 24 2009
  • Mathematica
    a=b=s=0;lst={a};Do[a+=n;b+=a;s+=b;AppendTo[lst,s],{n,6!}];lst+1 (* Vladimir Joseph Stephan Orlovsky, Jun 14 2009 *)
    CoefficientList[Series[(x^4 - 4 x^3 + 6 x^2 - 3 x + 1) / (1 - x)^5, {x, 0, 50}], x] (* Vincenzo Librandi, Jun 06 2013 *)
  • PARI
    Vec((x^4-4*x^3+6*x^2-3*x+1)/(1-x)^5 + O(x^50)) \\ Altug Alkan, Nov 24 2015

Formula

G.f.: (x^4-4*x^3+6*x^2-3*x+1) / (1-x)^5.
a(n) = C(n+3,4)+1. - Zerinvary Lajos, Mar 24 2009

A145140 Numerators of triangle T(n,k), n>=1, 0<=k<=n - 1, read by rows: T(n,k) is the coefficient of x^k in polynomial p_n for the n-th row sequence of A145153.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 11, 1, 1, 1, 6, 5, 7, 1, 1, 1, 5, 317, 5, 17, 1, 1, 1, 83, 27, 22, 7, 5, 1, 1, 2, 53, 5989, 1069, 1207, 7, 23, 1, 1, 3, 611, 2743, 93791, 149, 1213, 1, 13, 1, 1, 4, 101, 25523, 5419, 20071, 397, 3253, 1, 29, 1, 1, 5, 32419, 11017, 30731, 21757
Offset: 1

Views

Author

Alois P. Heinz, Oct 03 2008

Keywords

Examples

			1, 0, 1, 0, 1/2, 1/2, 0, 1/3, 1/2, 1/6, 1, 1/4, 11/24, 1/4, 1/24, 1, 6/5, 5/12, 7/24, 1/12, 1/120, 1, 5/3, 317/360, 5/16, 17/144, 1/48, 1/720 ... = A145140/A145141
As triangle:
  1
  0 1
  0 1/2 1/2
  0 1/3 1/2 1/6
  1 1/4 11/24 1/4 1/24
  1 6/5 5/12 7/24 1/12 1/120
		

Crossrefs

Denominators of T(n, k): A145141. T(n, k)*(n-1)!: A145142.
Row sums give: A003269, A017898(n+3).

Programs

  • Maple
    row:= proc(n) option remember; local f,i,x; f:= unapply(simplify(sum('cat(a||i) *x^i', 'i'=0..n-1) ), x); unapply(subs(solve({seq(f(i+1)= coeftayl(x/ (1-x-x^4)/ (1-x)^i, x=0, n), i=0..n-1)}, {seq(cat(a||i), i=0..n-1)}), sum('cat(a||i) *x^i', 'i'=0..n-1) ), x); end: T:= (n,k)-> coeff(row(n)(x), x, k): seq(seq(numer(T(n,k)), k=0..n-1), n=1..14);
  • Mathematica
    row[n_] := Module[{f, eq}, f = Function[x, Sum[a[k]*x^k, {k, 0, n-1}]]; eq = Table[f[k+1] == SeriesCoefficient[x/(1-x-x^4)/(1-x)^k, {x, 0, n}], {k, 0, n-1}]; Table[a[k], {k, 0, n-1}] /. Solve[eq] // First]; Table[row[n] // Numerator, {n, 1, 14}] // Flatten (* Jean-François Alcover, Feb 04 2014, after Alois P. Heinz *)

Formula

See program.

A145127 a(n) = 1 + (144 + (50 + (35 + (10 + n)*n)*n)*n)*n/120.

Original entry on oeis.org

1, 3, 9, 25, 61, 132, 259, 470, 801, 1297, 2013, 3015, 4381, 6202, 8583, 11644, 15521, 20367, 26353, 33669, 42525, 53152, 65803, 80754, 98305, 118781, 142533, 169939, 201405, 237366, 278287, 324664, 377025, 435931, 501977, 575793, 658045, 749436
Offset: 0

Views

Author

Alois P. Heinz, Oct 03 2008

Keywords

Comments

(1 + 3x + 9x^2 + ...) = (1 + 3x + 6x^2 + 10x^3 + ...) * (1 + 3x^2 + 6x^3 + 10x^4 + ...). - Gary W. Adamson, Jul 27 2010

Crossrefs

6th row of A145153. See row 6 of A145140/A145141 for rational coefficients and A145142 for 120 * coefficients of polynomial.

Programs

  • Magma
    [1 + (144 + (50 + (35 + (10 + n)*n)*n)*n)*n/120: n in [0..40]]; // Vincenzo Librandi, May 19 2011
  • Maple
    a := n-> 1+ (144+ (50+ (35+ (10+ n) *n) *n) *n) *n/120: seq (a(n), n=0..40);

Formula

G.f.: (x^4 - 4*x^3 + 6*x^2 - 3*x + 1) / (1-x)^6.

A145128 a(n) = 1 + (1200 + (634 + (225 + (85 + (15 + n)*n)*n)*n)*n)*n/720.

Original entry on oeis.org

1, 4, 13, 38, 99, 231, 490, 960, 1761, 3058, 5071, 8086, 12467, 18669, 27252, 38896, 54417, 74784, 101137, 134806, 177331, 230483, 296286, 377040, 475345, 594126, 736659, 906598, 1108003, 1345369, 1623656, 1948320, 2325345, 2761276, 3263253, 3839046, 4497091
Offset: 0

Views

Author

Alois P. Heinz, Oct 03 2008

Keywords

Crossrefs

7th row of A145153. See row 7 of A145140/A145141 for rational coefficients and A145142 for 720 * coefficients of polynomial.

Programs

  • Maple
    a := n-> 1+ (1200+ (634+ (225+ (85+ (15+ n) *n) *n) *n) *n) *n/720: seq (a(n), n=0..40);

Formula

G.f.: (x^4-4*x^3+6*x^2-3*x+1) / (1-x)^7.

A145129 1 + (9960 + (6804 + (2464 + (735 + (175 + (21 + n)*n)*n)*n)*n)*n)*n/5040.

Original entry on oeis.org

1, 5, 18, 56, 155, 386, 876, 1836, 3597, 6655, 11726, 19812, 32279, 50948, 78200, 117096, 171513, 246297, 347434, 482240, 659571, 890054, 1186340, 1563380, 2038725, 2632851, 3369510, 4276108, 5384111, 6729480, 8353136, 10301456, 12626801, 15388077, 18651330
Offset: 0

Views

Author

Alois P. Heinz, Oct 03 2008

Keywords

Crossrefs

8th row of A145153. See row 8 of A145140/A145141 for rational coefficients and A145142 for 5040 * coefficients of polynomial.

Programs

  • Maple
    a := n-> 1+ (9960+ (6804+ (2464+ (735+ (175+ (21+ n) *n) *n) *n) *n) *n) *n/5040: seq(a(n), n=0..40);
  • Mathematica
    CoefficientList[Series[(x^4 - 4 x^3 + 6 x^2 - 3 x + 1) / (1 - x)^8, {x, 0, 50}], x] (* Vincenzo Librandi, Jun 06 2013 *)

Formula

G.f.: (x^4-4*x^3+6*x^2-3*x+1) / (1-x)^8.

A145130 2 + (89040 + (71868 + (29932 + (8449 + (1960 + (322 + (28 + n)*n)*n)*n)*n)*n)*n)*n/40320.

Original entry on oeis.org

2, 7, 25, 81, 236, 622, 1498, 3334, 6931, 13586, 25312, 45124, 77403, 128351, 206551, 323647, 495160, 741457, 1088891, 1571131, 2230702, 3120756, 4307096, 5870476, 7909201, 10542052, 13911562, 18187670, 23571781, 30301261, 38654397, 48955853, 61582654
Offset: 0

Views

Author

Alois P. Heinz, Oct 03 2008

Keywords

Crossrefs

9th row of A145153. See row 9 of A145140/A145141 for rational coefficients and A145142 for 40320 * coefficients of polynomial.

Programs

  • Maple
    a:= n-> 2+ (89040+ (71868+ (29932+ (8449+ (1960+ (322+ (28+ n) *n) *n) *n) *n) *n) *n) *n/40320: seq (a(n), n=0..40);
  • Mathematica
    Table[2+(89040+(71868+(29932+(8449+(1960+(322+(28+n)n)n)n)n)n)n)n/40320,{n,0,40}] (* or *) LinearRecurrence[{9,-36,84,-126,126,-84,36,-9,1},{2,7,25,81,236,622,1498,3334,6931},40](* Harvey P. Dale, Dec 25 2011 *)
    CoefficientList[Series[(x^8 - 8 x^7 + 28 x^6 - 56 x^5 + 71 x^4 - 60 x^3 + 34 x^2 - 11 x + 2) / (1 - x)^9, {x, 0, 50}], x] (* Vincenzo Librandi, Jun 06 2013 *)
  • PARI
    a(n)=2+(89040+(71868+(29932+(8449+(1960+(322+(28+n)*n)*n)*n)*n)*n)*n)*n/40320 \\ Charles R Greathouse IV, Oct 07 2015

Formula

G.f.: (x^8-8*x^7+28*x^6-56*x^5+71*x^4-60*x^3+34*x^2-11*x+2) / (1-x)^9.
a(0)=2, a(1)=7, a(2)=25, a(3)=81, a(4)=236, a(5)=622, a(6)=1498, a(7)=3334, a(8)=6931, 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, Dec 25 2011
Showing 1-8 of 8 results.