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.

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A136482 Triangle read by rows: T(n,k) = 2*A007318(n,k) - A034851(n,k) (i.e., twice Pascal's triangle - the Losanitch triangle).

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 4, 4, 1, 1, 6, 8, 6, 1, 1, 7, 14, 14, 7, 1, 1, 9, 21, 30, 21, 9, 1, 1, 10, 30, 51, 51, 30, 10, 1, 1, 12, 40, 84, 102, 84, 40, 12, 1, 1, 13, 52, 124, 186, 186, 124, 52, 13, 1, 1, 15, 65, 180, 310, 378, 310, 180, 65, 15, 1, 1, 16, 80, 245, 490, 688, 688, 490, 245
Offset: 0

Views

Author

Gary W. Adamson, Dec 31 2007

Keywords

Comments

Row sums are apparently in A135098. - R. J. Mathar, May 01 2008

Examples

			Row n=3 is 2*(1,3,3,1) - (1,2,2,1) = (1,4,4,1).
		

Crossrefs

Programs

Extensions

Edited and corrected by R. J. Mathar, May 01 2008

A136488 a(n) = 2^n - A005418(n).

Original entry on oeis.org

1, 2, 5, 10, 22, 44, 92, 184, 376, 752, 1520, 3040, 6112, 12224, 24512, 49024, 98176, 196352, 392960, 785920, 1572352, 3144704, 6290432, 12580864, 25163776, 50327552, 100659200, 201318400, 402644992, 805289984, 1610596352, 3221192704, 6442418176, 12884836352
Offset: 1

Views

Author

Gary W. Adamson, Jan 01 2008

Keywords

Examples

			a(5) = 22 = 2^5 - A005418(5) = 32 - 10.
a(5) = 22 = sum of row 5 terms of triangle A136482 = (1 + 6 + 8 + 6 + 1).
		

Crossrefs

Programs

  • Magma
    [2^n - (2^(n - 2) + 2^(Floor(n/2) - 1)): n in [1..40]]; // G. C. Greubel, Nov 02 2018
  • Mathematica
    Table[2^n - (2^(n - 2) + 2^(Floor[n/2] - 1)), {n, 40}] (* after Harvey P. Dale at A005418, or *)
    CoefficientList[Series[(1 - x^2)/(1 - 2 x - 2 x^2 + 4 x^3), {x, 0, 40}], x] (* Michael De Vlieger, Sep 23 2016 *)
  • PARI
    Vec(x*(1-x)*(1+x)/((1-2*x)*(1-2*x^2)) + O(x^40)) \\ Colin Barker, Sep 23 2016
    

Formula

a(n) = 2^n - A005418(n). Sum of (n-1)-th row terms of triangle A136482.
G.f.: x*(1 - x^2)/(1 - 2*x - 2*x^2 + 4*x^3). - Michael De Vlieger, Sep 23 2016
From Colin Barker, Sep 23 2016: (Start)
a(n) = 3*2^(n-2)-2^(n/2-1) for n even.
a(n) = 3*2^(n-2)-2^((n-3)/2) for n odd.
(End)
a(n) = A135098(n-1) for n >= 1. - Georg Fischer, Nov 02 2018

Extensions

More terms from Colin Barker, Mar 19 2013
Missing a(4) added by Michael De Vlieger, Sep 23 2016
Showing 1-2 of 2 results.