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 31-37 of 37 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

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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.

A341109 a(n) = denominator(p(n, x)) / (n!*denominator(bernoulli(n, x))), where p(n, x) = Sum_{k=0..n} E2(n, k)*binomial(x + k, 2*n) / Product_{j=1..n} (j - x) and E2(n, k) are the second-order Eulerian numbers A201637.

Original entry on oeis.org

1, 1, 2, 4, 8, 16, 96, 192, 1152, 768, 1536, 3072, 18432, 36864, 221184, 147456, 884736, 1769472, 10616832, 21233664, 637009920, 424673280, 2548039680, 5096079360, 152882380800, 61152952320, 366917713920, 81537269760, 163074539520, 326149079040, 1956894474240
Offset: 0

Views

Author

Peter Luschny, Feb 06 2021

Keywords

Comments

The challenge is to characterize the sequence purely arithmetically, i.e., without reference to the Eulerian numbers or the Bernoulli polynomials.

Crossrefs

Programs

  • Maple
    Epoly := proc(n, x) add(combinat:-eulerian2(n, k)*binomial(x+k, 2*n), k = 0..n) / mul(j-x, j = 1..n): simplify(expand(%)) end:
    seq(denom(Epoly(n, x)) / (n!*denom(bernoulli(n, x))), n = 0..30);
  • Mathematica
    A053657[n_] := Product[p^Sum[Floor[(n-1)/((p-1) p^k)], {k,0,n}],{p, Prime[Range[n]]}];
    A144845[n_] := Denominator[Together[BernoulliB[n, x]]];
    A163176[n_] := A053657[n] / n!;
    Table[(n + 1) A163176[n + 1] / A144845[n], {n, 0, 30}]
  • Sage
    def A341109(n): # uses[A341108, A318256]
        return A341108(n)//A318256(n)
    print([A341109(n) for n in (0..30)])

Formula

a(n) = A053657(n+1)/(n!*A144845(n)).
a(n) = (n+1)*A163176(n+1)/A144845(n).
a(n) = A341108(n)/A318256(n).
a(n) = A341107(n)*A324369(n+1).
a(n) = A341108(n)/A324370(n+1).
a(n) = A341108(n)*A007947(n+1)/A144845(n).
a(n) = A341108(n)*A324369(n+1)/A195441(n).
prime(n) divides a(k) for k >= A036689(n).
2^(n-1) divides exactly a(n) for n >= 2.

A202717 Triangle of numerators of coefficients of the polynomial Q^(3)m(n) defined by the recursion Q^(3)_0(n)=1; for m>=1, Q^(3)_m(n) = Sum{i=1...n} i^3*Q^(3)_(m-1)(i).

Original entry on oeis.org

1, 1, 2, 1, 0, 0, 21, 132, 294, 252, 21, -56, 0, 8, 0, 35, 450, 2293, 5700, 6405, 770, -3661, -240, 2320, 40, -672, 0, 0, 9555, 207480, 1889316, 9216312, 25051026, 33229560, 3678948, -35339304, -2666157, 51171120, 2178176, -49878192, -792064, 24460800, 4160, -3714816, 0
Offset: 0

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Author

Keywords

Comments

For m>=0, the denominator for all 4*m+1 terms of the m-th row is A202368(m+1).
See comment to A175669.

Examples

			The sequence of polynomials begins
Q^(3)_0=1,
Q^(3)_1=(x^4+2*x^3+x^2)/4,
Q^(3)_2=(21*x^8+132*x^7+294*x^6+252*x^5+21*x^4-56*x^3+8*x)/672,
Q^(3)_3=(35*x^12+450*x^11+2293*x^10+5700*x^9+6405*x^8+770*x^7-3661*x^6-240*x^5+2320*x^4+40x^3-672*x^2)/13440.
		

Crossrefs

Formula

Q^(3)_n(1)=1.

A342645 Triangle read by rows: T(n,k) gives n! times the coefficient of x^k in the polynomial that describes the number of permutations on x letters with major index n.

Original entry on oeis.org

1, -1, 1, -2, -1, 1, 0, -7, 0, 1, 0, -14, -13, 2, 1, 120, -46, -65, -15, 5, 1, 0, 516, -356, -165, -5, 9, 1, 5040, 1392, 266, -1421, -280, 28, 14, 1, 0, 46320, 3772, -5740, -3871, -280, 98, 20, 1, 0, 215280, 212724, -26272, -31437, -7791, 126, 222, 27, 1
Offset: 0

Views

Author

Peter Kagey, Mar 17 2021

Keywords

Comments

This n-th row describes a polynomial that eventually agrees with the n-th column of A008302.
Conjecture: For each m, T(n,n-m) is a polynomial of degree 2m whose leading coefficient is abs(A290030(m)/A053657(m+1)).

Examples

			n\k |    0       1       2       3       4      5    6    7   8  9
----+--------------------------------------------------------------
  0 |    1;
  1 |   -1,      1;
  2 |   -2,     -1,      1;
  3 |    0,     -7,      0,      1;
  4 |    0,    -14,    -13,      2,      1;
  5 |  120,    -46,    -65,    -15,      5,     1;
  6 |    0,    516,   -356,   -165,     -5,     9,   1;
  7 | 5040,   1392,    266,  -1421,   -280,    28,  14,   1;
  8 |    0,  46320,   3772,  -5740,  -3871,  -280,  98,  20,  1;
  9 |    0, 215280, 212724, -26272, -31437, -7791, 126, 222, 27, 1;
For n = 4, the polynomial that describes the 4th column of A008302 is
A008302(x,4) = (-14x -13x^2 +2x^3 + x^4)/4! = Sum_{j=0..4} (T(j,4)*x^j)/4!.
		

Crossrefs

Programs

Formula

Conjectures:
T(n,n) = 1.
T(n,n-1) = (-3n + n^2)/2.
T(n,n-2) = (-2n + 21n^2 - 22n^3 + 3n^4)/24.
T(n,n-3) = (96n - 134n^2 + 13n^3 + 37n^4 - 13n^5 + n^6)/48.

A153359 Scaled coefficients of the M. O. Rubinstein polynomials.

Original entry on oeis.org

1, -1, 1, -2, -1, 3, -2, -1, 2, 1, -152, -78, 125, 90, 15, -216, -114, 157, 135, 35, 3, -41424, -22444, 27552, 26551, 8505, 1197, 63, -66000, -36620, 40976, 42917, 15652, 2814, 252, 9, -13037952, -7390832, 7652084, 8557940, 3414775, 714840, 83790, 5220, 135, -21995904
Offset: 0

Views

Author

Peter Luschny, Dec 24 2008

Keywords

Comments

The polynomials alpha_{k}(s) are defined in formula (1.4) in the paper cited below. The coefficients are in ascending order.

Examples

			alpha_{0}(t) = 1 / 1;
alpha_{1}(t) = (-1 + t) / 2;
alpha_{2}(t) = (-2 - t + 3t^2) / 24;
alpha_{3}(t) = (-2 - t + 2t^2 + t^3) / 48;
		

Crossrefs

Cf. A053657.

Programs

  • Mathematica
    alpha[0, ] = 1; alpha[k, s_] := (s - 1)/(k + 1) - Sum[((j - (s - 1)*(k - j))/(k - j + 1))*alpha[j, s]/(k), {j, 1, k - 1}] // Expand;
    a53657[n_] := Product[p^Sum[Floor[(n - 1)/((p - 1) p^k)], {k, 0, n}], {p, Prime[Range[n]]}];
    row[k_] := CoefficientList[alpha[k, t]*a53657[k + 1], t];
    Table[row[k], {k, 0, 7}] // Flatten (* Jean-François Alcover, Jul 19 2018 *)

Formula

The coefficients of the polynomials alpha_{k}(s)*A053657(k) where alpha_{0}(s) = 1 and alpha_{k+1}(s) = (s-1)/(k+2)-sum(j=1..k,((j-(s-1)*(k-j+1))/(k-j+2))*alpha_{j}(s))/(k+1).

Extensions

More terms from Giovanni Resta, Jul 19 2018

A163394 The odd part of Minkowski(n)/n!

Original entry on oeis.org

1, 1, 1, 1, 1, 3, 1, 9, 9, 15, 3, 9, 3, 945, 135, 27, 27, 405, 45, 8505, 1701, 66825, 6075, 18225, 6075, 995085, 76545, 8505, 1215, 18225, 1215, 841995, 841995, 6506325, 382725, 32805, 3645, 850797675, 44778825, 3444525
Offset: 0

Views

Author

Peter Luschny, Jul 26 2009

Keywords

Crossrefs

Programs

  • Maple
    a := proc(n) local L,p;
    L := proc(n,p,r) local q,s,m; m:=n-r; q:=p-r; s:=0;
    do if q > n then break fi; s := s+iquo(m,q);
    q := q*p od; s end; mul(p^(L(n,p,1)-L(n,p,0)),
    p = select(isprime,[$3..n])); end
  • Mathematica
    L[n_, p_, r_] := Module[{q, s, m}, m = n-r; q = p-r; s = 0; While[True, If[ q > n, Break[]]; s = s + Quotient[m, q]; q = q*p]; s];
    a[n_] := Product[p^(L[n, p, 1]-L[n, p, 0]), {p, Select[Range[3, n], PrimeQ] }];
    Table[a[n], {n, 0, 39}] (* Jean-François Alcover, Jun 17 2019 *)

Formula

a(n) = A000265(A163176(n)). - Michel Marcus, Jun 17 2019

A202749 Triangle of numerators of coefficients of the polynomial Q^(4)m(n) defined by the recursion Q^(4)_0(n)=1; for m>=1,Q^(4)_m(n)=sum{i=1,...,n}i^4*Q^(4)(m-1)(i). For m>=0, the denominator for all 5*m+1 terms of the m-th row is A202369(m+1).

Original entry on oeis.org

1, 6, 15, 10, 0, -1, 0, 36, 280, 795, 900, 88, -450, -20, 200, 1, -30, 0, 19656, 311220, 1991430, 6354075, 9367722, 1283100, -10854935, -1064700, 16237338, 615615, -16336320, -136500, 8189909, 8190, -1243800, 0
Offset: 0

Views

Author

Keywords

Comments

See comment in A175669.

Examples

			The sequence of polynomials begins
Q^(3)_0=1,
Q^(3)_1=(6*x^5+15*x^4+10*x^3-x)/30,
Q^(3)_2=(36*x^10+280*x^9+795*x^8+900*x^7+88*x^6-450*x^5-20*x^4+200*x^3+x^2-30*x)/1800.
		

Crossrefs

Formula

Q^(4)_n(1)=1.
Previous Showing 31-37 of 37 results.