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.

A096979 Sum of the areas of the first n+1 Pell triangles.

Original entry on oeis.org

0, 1, 6, 36, 210, 1225, 7140, 41616, 242556, 1413721, 8239770, 48024900, 279909630, 1631432881, 9508687656, 55420693056, 323015470680, 1882672131025, 10973017315470, 63955431761796, 372759573255306, 2172602007770041
Offset: 0

Views

Author

Paul Barry, Jul 17 2004

Keywords

Comments

Convolution of A059841(n) and A001109(n+1).
Partial sums of A084158.

Crossrefs

Programs

  • Mathematica
    Accumulate[LinearRecurrence[{5,5,-1},{0,1,5},30]] (* Harvey P. Dale, Sep 07 2011 *)
    LinearRecurrence[{6, 0, -6, 1},{0, 1, 6, 36},22] (* Ray Chandler, Aug 03 2015 *)

Formula

G.f.: x/((1-x)*(1+x)*(1-6*x+x^2)).
a(n) = 6*a(n-1)-6*a(n-3)+a(n-4).
a(n) = (3-2*sqrt(2))^n*(3/32-sqrt(2)/16)+(3+2*sqrt(2))^n*(sqrt(2)/16+3/32)-(-1)^n/16-1/8.
a(n) = Sum_{k=0..n} (sqrt(2)*(sqrt(2)+1)^(2*k)/8-sqrt(2)*(sqrt(2)-1)^(2*k)/8)*(1+(-1)^(n-k))/2.
a(n) = Sum_{k=0..n} A000129(k)*A000129(k+1)/2. [corrected by Jason Yuen, Jan 14 2025]
a(n) = (A001333(n+1)^2 - 1)/8 = ((A000129(n) + A000129(n+1))^2 - 1)/8. - Richard R. Forberg, Aug 25 2013
a(n) = A002620(A000129(n+1)) = A000217(A048739(n-1)), n > 0. - Ivan N. Ianakiev, Jun 21 2014

A096978 Sum of the areas of the first n Jacobsthal rectangles.

Original entry on oeis.org

0, 1, 4, 19, 74, 305, 1208, 4863, 19398, 77709, 310612, 1242907, 4970722, 19884713, 79535216, 318148151, 1272578046, 5090341317, 20361307020, 81445344595, 325781145370, 1303125047521, 5212499258024, 20849998896239, 83399991856694
Offset: 0

Views

Author

Paul Barry, Jul 17 2004

Keywords

Crossrefs

Programs

  • Magma
    [8*4^n/27-2*(-2)^n/27-(n+2)/9: n in [0..30]]; // Vincenzo Librandi, May 31 2011
  • Mathematica
    LinearRecurrence[{4,3,-14,8},{0,1,4,19},30] (* or *) Table[(2^(2n+1)-3n - 3+(-2)^n)/27,{n,30}] (* Harvey P. Dale, Aug 08 2011 *)

Formula

G.f.: x/((1-x)^2*(1+2*x)*(1-4*x)).
a(n) = 8*4^n/27 - 2*(-2)^n/27 - (n+2)/9;
a(n) = Sum_{k=0..n} (2*4^k/3 + (-2)^k/3)*(n-k).
a(n) = 4*a(n-1) + 3*a(n-2) - 14*a(n-3) + 8*a(n-4).
a(n) = Sum_{k=0..n} A001045(k)*A001045(k+1).
a(n-1) = Sum_{k=0..n} (-1)^(k+1)*A001045(k)*A001045(2*(n-k)). - Paul Barry, Aug 11 2009
Showing 1-2 of 2 results.