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.

A095666 Pascal (1,4) triangle.

Original entry on oeis.org

4, 1, 4, 1, 5, 4, 1, 6, 9, 4, 1, 7, 15, 13, 4, 1, 8, 22, 28, 17, 4, 1, 9, 30, 50, 45, 21, 4, 1, 10, 39, 80, 95, 66, 25, 4, 1, 11, 49, 119, 175, 161, 91, 29, 4, 1, 12, 60, 168, 294, 336, 252, 120, 33, 4, 1, 13, 72, 228, 462, 630, 588, 372, 153, 37, 4, 1, 14, 85, 300, 690, 1092
Offset: 0

Views

Author

Wolfdieter Lang, Jun 11 2004

Keywords

Comments

This is the fourth member, q=4, in the family of (1,q) Pascal triangles: A007318 (Pascal (q=1)), A029635 (q=2) (but with a(0,0)=2, not 1), A095660 (q=3), A096940 (q=5), A096956 (q=6).
This is an example of a Riordan triangle (see A053121 for a comment and the 1991 Shapiro et al. reference on the Riordan group) with o.g.f. of column no. m of the type g(x)*(x*f(x))^m with f(0)=1. Therefore the o.g.f. for the row polynomials p(n,x) := Sum_{m=0..n} a(n,m)*x^m is G(z,x) = g(z)/(1 - x*z*f(z)). Here: g(x) = (4-3*x)/(1-x), f(x) = 1/(1-x), hence G(z,x) = (4-3*z)/(1-(1+x)*z).
The SW-NE diagonals give Sum_{k=0..ceiling((n-1)/2)} a(n-1-k, k) = A022095(n-2), n >= 2, with n=1 value 4. [Observation by Paul Barry, Apr 29 2004. Proof via recursion relations and comparison of inputs.]
T(2*n,n) = A029609(n) for n > 0, A029609 are the central terms of the Pascal (2,3) triangle A029600. - Reinhard Zumkeller, Apr 08 2012

Examples

			Triangle begins:
  [4];
  [1,4];
  [1,5,4];
  [1,6,9,4];
  [1,7,15,13,4];
  ...
		

Crossrefs

Row sums: A020714(n-1), n >= 1, 4 if n=0.
Alternating row sums are [4, -3, followed by 0's].
Column sequences (without leading zeros) give for m=1..9, with n >= 0: A000027(n+4), A055999(n+1), A060488(n+3), A095667-71, A095819.

Programs

  • Haskell
    a095666 n k = a095666_tabl !! n !! k
    a095666_row n = a095666_tabl !! n
    a095666_tabl = [4] : iterate
       (\row -> zipWith (+) ([0] ++ row) (row ++ [0])) [1,4]
    -- Reinhard Zumkeller, Apr 08 2012
  • Maple
    a(n,k):=(1+3*k/n)*binomial(n,k) # Mircea Merca, Apr 08 2012
  • Mathematica
    A095666[n_, k_] := If[n == k,  4, (3*k/n + 1)*Binomial[n, k]];
    Table[A095666[n, k], {n, 0, 12}, {k, 0, n}] (* Paolo Xausa, Apr 14 2025 *)

Formula

Recursion: a(n, m) = 0 if m > n, a(0, 0) = 4; a(n, 0) = 1 if n>=1; a(n, m) = a(n-1, m) + a(n-1, m-1).
G.f. column m (without leading zeros): (4-3*x)/(1-x)^(m+1), m >= 0.
a(n,k) = (1 + 3*k/n)*binomial(n,k). - Mircea Merca, Apr 08 2012

A146523 Binomial transform of A010685.

Original entry on oeis.org

1, 5, 10, 20, 40, 80, 160, 320, 640, 1280, 2560, 5120, 10240, 20480, 40960, 81920, 163840, 327680, 655360, 1310720, 2621440, 5242880, 10485760, 20971520, 41943040, 83886080, 167772160, 335544320, 671088640, 1342177280, 2684354560, 5368709120, 10737418240
Offset: 0

Views

Author

Philippe Deléham, Oct 30 2008

Keywords

Comments

Linked to A029609 by a Catalan transform.
Hankel transform is (1, -15, 0, 0, 0, 0, 0, 0, 0, ...).

Crossrefs

Programs

Formula

a(n) = 5*2^(n-1) for n >= 1, a(0) = 1.
a(n) = Sum_{k=0..n} A109466(n,k)*A029609(k).
a(n) = A084215(n+1) = A020714(n-1), n > 0. - R. J. Mathar, Nov 02 2008
G.f.: (1 + 3*x)/(1 - 2*x). - Vladimir Joseph Stephan Orlovsky, Jun 21 2011
G.f.: G(0), where G(k)= 1 + 3*x/(1 - 2*x/(2*x + 3*x/G(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Jul 03 2013
E.g.f.: (5*exp(2*x) - 3)/2. - Stefano Spezia, Feb 20 2023

A146533 Catalan transform of A135092.

Original entry on oeis.org

1, 7, 21, 70, 245, 882, 3234, 12012, 45045, 170170, 646646, 2469012, 9464546, 36402100, 140408100, 542911320, 2103781365, 8167621770, 31762973550, 123708423300, 482462850870, 1883902560540, 7364346373020, 28817007546600, 112866612890850, 442437122532132, 1735714865318364
Offset: 0

Views

Author

Philippe Deléham, Oct 31 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_]:=(7*Binomial[2n,n]-5*KroneckerDelta[n,0])/2; Array[a,27,0] (* Stefano Spezia, Feb 14 2025 *)

Formula

a(n) = Sum_{k=0..n} A039599(n,k)*A010687(k) = Sum_{k=0..n} A106566(n,k)*A135092(k).
a(n) = (7*C(2n,n) - 5*0^n)/2.
From Stefano Spezia, Feb 14 2025: (Start)
G.f.: (7/sqrt(1 - 4*x) - 5)/2.
E.g.f.: (7*exp(2*x)*BesselI(0, 2*x) - 5)/2. (End)

Extensions

a(23)-a(26) from Stefano Spezia, Feb 14 2025

A146534 a(n) = 4*C(2n,n) - 3*0^n.

Original entry on oeis.org

1, 8, 24, 80, 280, 1008, 3696, 13728, 51480, 194480, 739024, 2821728, 10816624, 41602400, 160466400, 620470080, 2404321560, 9334424880, 36300541200, 141381055200, 551386115280, 2153031497760, 8416395854880, 32933722910400, 128990414732400, 505642425751008, 1983674131792416
Offset: 0

Views

Author

Philippe Deléham, Oct 31 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_]:=4*Binomial[2n,n]-3*KroneckerDelta[n,0]; Array[a,27,0] (* Stefano Spezia, Feb 14 2025 *)

Formula

a(n) = Sum_{k=0..n} A039599(n,k)*A010688(k).
From Stefano Spezia, Feb 14 2025: (Start)
G.f.: 4/sqrt(1 - 4*x) - 3.
E.g.f.: 4*exp(2*x)*BesselI(0, 2*x) - 3. (End)

Extensions

a(22)-a(26) from Stefano Spezia, Feb 14 2025
Showing 1-4 of 4 results.