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.

A154222 Row sums of number triangle A154221.

Original entry on oeis.org

1, 2, 4, 8, 17, 38, 87, 200, 457, 1034, 2315, 5132, 11277, 24590, 53263, 114704, 245777, 524306, 1114131, 2359316, 4980757, 10485782, 22020119, 46137368, 96469017, 201326618, 419430427, 872415260, 1811939357, 3758096414, 7784628255, 16106127392, 33285996577
Offset: 0

Views

Author

Paul Barry, Jan 05 2009

Keywords

Crossrefs

Programs

  • Magma
    [(1/4)*(4*(n+1)+(n-1)*2^n+0^n): n in [0..35]]; // Vincenzo Librandi, Sep 07 2016
  • Mathematica
    Join[{1},LinearRecurrence[{6, -13, 12, -4}, {2, 4, 8,17}, 25]] (* or *) Table[(1/4)*( 4*(n+1) + (n-1)*2^n + 0^n), {n,0,25}] (* G. C. Greubel, Sep 06 2016 *)
  • PARI
    Vec((x^4-2*x^3+5*x^2-4*x+1)/((x-1)^2*(2*x-1)^2) + O(x^100)) \\ Colin Barker, Oct 11 2014
    

Formula

a(n) = (1/4)*( 4*(n+1) + (n-1)*2^n + 0^n).
From Colin Barker, Oct 11 2014: (Start)
a(n) = A045618(n-4) + 2^n for n>3.
a(n) = 6*a(n-1) - 13*a(n-2) + 12*a(n-3) - 4*a(n-4) for n>4.
a(n) = (4 - 2^n + (4+2^n)*n)/4 for n>0.
G.f.: (x^4 - 2*x^3 + 5*x^2 - 4*x + 1) / ((x-1)^2*(2*x-1)^2).
(End)
E.g.f.: (1/4)*(1 + 4*(1 + x)*exp(x) + (2*x - 1)*exp(2*x)). - G. C. Greubel, Sep 06 2016

Extensions

More terms and xrefs from Colin Barker, Oct 11 2014

A154223 Diagonal sums of number triangle A154221.

Original entry on oeis.org

1, 1, 2, 3, 5, 9, 16, 32, 61, 125, 246, 502, 999, 2023, 4040, 8136, 16265, 32649, 65290, 130826, 261643, 523787, 1047564, 2096140, 4192269, 8386573, 16773134, 33550350, 67100687, 134209551, 268419088, 536854544, 1073709073, 2147450897, 4294901778, 8589869074, 17179738131, 34359607315, 68719214612, 137438691348
Offset: 0

Views

Author

Paul Barry, Jan 05 2009

Keywords

Programs

  • Magma
    I:=[1,1,2,3,5,9,16]; [n le 7 select I[n] else 3*Self(n-1)+Self(n-2)-9*Self(n-3)+4*Self(n-4)+6*Self(n-5)-4*Self(n-6): n in [1..40]]; // Vincenzo Librandi, Sep 07 2016
    
  • Maple
    A154223 := proc(n)
        a := 0 ;
        for npr from n by -1 do
            k := n-npr ;
            if k <= npr then
                a := a+A154221(npr,k) ;
            else
                return a;
            end if;
        end do:
    end proc: # R. J. Mathar, Feb 05 2015
  • Mathematica
    Join[{1}, LinearRecurrence[{3, 1, -9, 4, 6, -4}, {1, 2, 3, 5, 9, 16}, 25]] (* G. C. Greubel, Sep 06 2016 *)
  • PARI
    Vec((1-x-x^2)*(1-x-2*x^2+2*x^3-x^4)/((1-x)^2*(1+x)*(1-2*x)*(1-2*x^2)) + O(x^40)) \\ Colin Barker, Sep 07 2016

Formula

G.f.: (1 - x - x^2)*(1 - x - 2*x^2 + 2*x^3 - x^4) / ((1-x)^2*(1+x)*(1-2*x)*(1-2*x^2)). - Colin Barker, Sep 07 2016
Showing 1-2 of 2 results.