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.

A181658 Row sums of A181657.

Original entry on oeis.org

1, 2, 3, 7, 8, 19, 20, 48, 49, 118, 119, 287, 288, 695, 696, 1680, 1681, 4058, 4059, 9799, 9800, 23659, 23660, 57120, 57121, 137902, 137903, 332927, 332928, 803759, 803760, 1940448, 1940449, 4684658, 4684659, 11309767, 11309768, 27304195, 27304196
Offset: 0

Views

Author

Paul Barry, Nov 03 2010

Keywords

Crossrefs

Cf. A048739 (bisection).

Programs

  • Mathematica
    CoefficientList[Series[(1+2x+x^3)/(1-3x^2+x^4+x^6),{x,0,40}],x] (* or *) LinearRecurrence[{0,3,0,-1,0,-1},{1,2,3,7,8,19},40] (* Harvey P. Dale, Mar 29 2022 *)

Formula

G.f.: (1+2x+x^3)/(1-3x^2+x^4+x^6)=(1+2x+x^3)/((1-x^2)(1-2x^2-x^4)).

A181656 Generalized (conditional) Riordan array with k-th column generated by x^k*(1+x^2) if k mod 2 = 0, x^k*(1+x) otherwise.

Original entry on oeis.org

1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1
Offset: 0

Views

Author

Paul Barry, Nov 03 2010

Keywords

Comments

A181657 is an eigentriangle for this triangle.

Examples

			Triangle begins
  1;
  0, 1;
  1, 1, 1;
  0, 0, 0, 1;
  0, 0, 1, 1, 1;
  0, 0, 0, 0, 0, 1;
  0, 0, 0, 0, 1, 1, 1;
  0, 0, 0, 0, 0, 0, 0, 1;
  0, 0, 0, 0, 0, 0, 1, 1, 1;
  0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
  0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1;
Production matrix begins
   0,  1;
   1,  1,  1;
  -1, -2, -1,  1;
   0,  0,  1,  1,  1;
   1,  2,  0, -2, -1,  1;
   0,  0,  0,  0,  1,  1,  1;
  -1, -2,  0,  2,  0, -2, -1,  1;
   0,  0,  0,  0,  0,  0,  1,  1,  1;
   1,  2,  0, -2,  0,  2,  0, -2, -1,  1;
   0,  0,  0,  0,  0,  0,  0,  0,  1,  1,  1;
		
Showing 1-2 of 2 results.