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 1-4 of 4 results.

A202481 Column k = 3 of triangular array in A165241.

Original entry on oeis.org

1, 10, 55, 231, 833, 2720, 8280, 23920, 66352, 178176, 465920, 1191680, 2991360, 7389184, 17999872, 43315200, 103116800, 243138560, 568393728, 1318518784, 3037265920, 6952058880, 15820390400, 35809918976, 80659611648
Offset: 0

Views

Author

Philippe Deléham, Dec 20 2011

Keywords

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{8,-24,32,-16},{1,10,55,231,833},30] (* Harvey P. Dale, Dec 04 2018 *)

Formula

G.f.: (1+2x-x^2-x^3+x^4)/(1-2x)^4.
a(n) = A165241(n+3,3).
a(n) = 2^n*(n+3)*(3*n+2)*(3*n+5)/32 for n>0. - Bruno Berselli, Dec 21 2011

A202493 Column k = 4 of triangular array in A165241.

Original entry on oeis.org

1, 15, 105, 532, 2241, 8361, 28610, 91740, 279624, 818272, 2315712, 6372480, 17123840, 45082368, 116596224, 296879104, 745543680, 1849344000, 4536958976, 11020075008, 26526547968, 63329075200, 150057123840
Offset: 0

Views

Author

Philippe Deléham, Dec 20 2011

Keywords

Crossrefs

Formula

a(n) = A165241(n+4,4).
G.f.: (1+5x-5x^2+2x^3+x^4-x^5)/(1-2x)^5.
a(n) = 2^n*(n+4)*(27*n^3+126*n^2+169*n+62)/256 for n>0. - Bruno Berselli, Dec 21 2011

Extensions

a(12) added by Bruno Berselli, Dec 21 2011

A210754 Triangle of coefficients of polynomials v(n,x) jointly generated with A210753; see the Formula section.

Original entry on oeis.org

1, 3, 2, 6, 9, 4, 10, 25, 24, 8, 15, 55, 85, 60, 16, 21, 105, 231, 258, 144, 32, 28, 182, 532, 833, 728, 336, 64, 36, 294, 1092, 2241, 2720, 1952, 768, 128, 45, 450, 2058, 5301, 8361, 8280, 5040, 1728, 256, 55, 660, 3630, 11385, 22363, 28610, 23920
Offset: 1

Views

Author

Clark Kimberling, Mar 25 2012

Keywords

Comments

Column 1: triangular numbers, A000217
Coefficient of v(n,x): 2^(n-1)
Row sums: A035344
Alternating row sums: 1,1,1,1,1,1,1,1,1,...
For a discussion and guide to related arrays, see A208510.
Appears to be the reversed row polynomials of A165241 with the unit diagonal removed. If so, the o.g.f. is [1-(1+y)x]/[1-2(1+y)x+(1+y)x^2] - 1/(1-x) and the triangular matrix here may be formed by adding each column of the matrix of A056242, presented in the example section with the additional zeros, to its subsequent column with the first row ignored. - Tom Copeland, Jan 09 2017

Examples

			First five rows:
1
3....2
6....9....4
10...25...24...8
15...55...85...60...16
First three polynomials v(n,x): 1, 3 + 2x, 6 + 9x +4x^2
		

Crossrefs

Programs

  • Mathematica
    u[1, x_] := 1; v[1, x_] := 1; z = 16;
    u[n_, x_] := (x + 1)*u[n - 1, x] + x*v[n - 1, x] + 1;
    v[n_, x_] := (x + 1)*u[n - 1, x] + (x + 1)*v[n - 1, x] + 1;
    Table[Expand[u[n, x]], {n, 1, z/2}]
    Table[Expand[v[n, x]], {n, 1, z/2}]
    cu = Table[CoefficientList[u[n, x], x], {n, 1, z}];
    TableForm[cu]
    Flatten[%]    (* A210753 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]    (* A210754 *)
    Table[u[n, x] /. x -> 1, {n, 1, z}] (* A007070 *)
    Table[v[n, x] /. x -> 1, {n, 1, z}] (* A035344 *)

Formula

u(n,x)=(x+1)*u(n-1,x)+x*v(n-1,x)+1,
v(n,x)=(x+1)*u(n-1,x)+(x+1)*v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.

A202480 Riordan array (1/(1-x), x(2x-1)/(1-x)^2).

Original entry on oeis.org

1, 1, -1, 1, -1, 1, 1, 0, 1, -1, 1, 2, -1, -1, 1, 1, 5, -5, 2, 1, -1, 1, 9, -10, 8, -3, -1, 1, 1, 14, -14, 14, -11, 4, 1, -1, 1, 20, -14, 14, -17, 14, -5, -1, 1, 1, 27, -6, 0, -9, 19, -17, 6, 1, -1
Offset: 0

Views

Author

Philippe Deléham, Dec 20 2011

Keywords

Comments

Row sums are Fibonacci(n-1) = A000045(n-1).
Diagonal sums are A078003(n).
(Sum_{j, 0<=j<=k} T(k,j))/(1-2x)^k gives g.f. of column A165241(n+k-1,k-1) in triangular array in A165241.

Examples

			Triangle begins :
1
1, -1
1, -1, 1
1, 0, 1, -1
1, 2, -1, -1, 1
1, 5, -5, 2, 1, -1
1, 9, -10, 8, -3, -1, 1
1, 14, -14, 14, -11, 4, 1, -1
(1+x^2-x^3)/(1-2x)^3 is the g.f of column A165241(n+2,2) := 1, 6, 25, 85, 258, 728, 1952, 5040, ...
		

Crossrefs

Formula

T(n,k) = 2*T(n-1,k) + 2*T(n-2,k-1) - T(n-1,k-1) - T(n-2,k).
T(n,k) = (-1)^n*A124341(n,k).
Showing 1-4 of 4 results.