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.

A193788 Triangular array: the fusion of polynomial sequences P and Q given by p(n,x)=(x+1)^n and q(n,x)=1+x^n.

Original entry on oeis.org

1, 1, 1, 2, 1, 3, 4, 4, 1, 9, 8, 12, 6, 1, 27, 16, 32, 24, 8, 1, 81, 32, 80, 80, 40, 10, 1, 243, 64, 192, 240, 160, 60, 12, 1, 729, 128, 448, 672, 560, 280, 84, 14, 1, 2187, 256, 1024, 1792, 1792, 1120, 448, 112, 16, 1, 6561, 512, 2304, 4608, 5376, 4032, 2016
Offset: 0

Views

Author

Clark Kimberling, Aug 05 2011

Keywords

Comments

See A193722 for the definition of fusion of two sequences of polynomials or triangular arrays.

Examples

			First six rows:
1
1....1
2....1....3
4....4....1....9
8....12...6....1...27
16...32...24...8...1...81
 (viz., A038207 with row sums at end of rows)
		

Crossrefs

Programs

  • Mathematica
    z = 10; a = 1; b = 2;
    p[n_, x_] := (a*x + b)^n
    q[n_, x_] := 1 + x^n ; q[n_, 0] := q[n, x] /. x -> 0;
    t[n_, k_] := Coefficient[p[n, x], x^k]; t[n_, 0] := p[n, x] /. x -> 0;
    w[n_, x_] := Sum[t[n, k]*q[n + 1 - k, x], {k, 0, n}]; w[-1, x_] := 1
    g[n_] := CoefficientList[w[n, x], {x}]
    TableForm[Table[Reverse[g[n]], {n, -1, z}]]
    Flatten[Table[Reverse[g[n]], {n, -1, z}]]  (* A193788 *)
    TableForm[Table[g[n], {n, -1, z}]]
    Flatten[Table[g[n], {n, -1, z}]]  (* A193789 *)

A182059 Triangle, read by rows, given by (0, 2, -1/2, 1/2, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (2, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938.

Original entry on oeis.org

1, 0, 2, 0, 4, 4, 0, 6, 12, 8, 0, 8, 24, 32, 16, 0, 10, 40, 80, 80, 32, 0, 12, 60, 160, 240, 192, 64, 0, 14, 84, 280, 560, 672, 448, 128, 0, 16, 112, 448, 1120, 1792, 1792, 1024, 256, 0, 18, 144, 672, 2016, 4032, 5376, 4608, 2304, 512
Offset: 0

Views

Author

Philippe Deléham, Apr 09 2012

Keywords

Comments

Row sums are 3^n - 1 + 0^n.
Triangle of coefficients in expansion of (1+2*x)^n - 1 + 0^n .

Examples

			Triangle begins :
1
0, 2
0, 4, 4
0, 6, 12, 8
0, 8, 24, 32, 16
0, 10, 40, 80, 80, 32
0, 12, 60, 160, 240, 192, 64
0, 14, 84, 280, 560, 672, 448, 128
0, 16, 112, 448, 1120, 1792, 1792, 1024, 256
0, 18, 144, 672, 2016, 4032, 5376, 4608, 2304, 512
0, 20, 180, 960, 3360, 8064, 13440, 15360, 11520, 5120, 1024
		

Crossrefs

Formula

G.f.: (1-2*x+x^2+2*y*x^2)/(1-2*x-2*y*x+x^2+2*y*x^2).
T(n,k) = 2*T(n-1,k) + 2*T(n-1,k-1) - T(n-2,k) - 2*T(n-2,k-1), T(0,0) = 1, T(1,0) = T(2,0) = 0, T(1,1) = 2, T(2,1) = T(2,2) = 4 and T(n,k) = 0 if k<0 or if k>n.
T(n,k) = A206735(n,k)*2^k.
T(n,k) = A013609(n,k) - A073424(n,k) .
Showing 1-2 of 2 results.