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.

Previous Showing 11-15 of 15 results.

A208704 Number of nX3 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.

Original entry on oeis.org

4, 28, 196, 1372, 9604, 67228, 470596, 3294172, 23059204, 161414428, 1129900996, 7909306972, 55365148804, 387556041628, 2712892291396, 18990246039772, 132931722278404, 930522055948828, 6513654391641796, 45595580741492572
Offset: 1

Views

Author

R. H. Hardin, Mar 01 2012

Keywords

Comments

Column 3 of A208709.

Examples

			Some solutions for n=4
..0..0..0....0..1..1....0..0..1....0..1..1....0..1..1....0..1..1....0..0..1
..1..0..1....1..0..1....0..0..1....0..1..1....1..0..0....1..0..1....0..1..1
..1..0..1....0..1..0....0..0..1....0..1..1....1..1..1....1..1..1....0..0..0
..1..0..1....0..1..0....1..1..1....0..1..1....1..0..1....1..0..1....0..1..0
		

Crossrefs

Cf. A270471.

Formula

Empirical: a(n) = 7*a(n-1).
Empirical: a(n) = (A198480(n)+1)*2 = (A024075(n)+1)*4. [Martin Ettl, Nov 09 2012; revised Nov 13 2012]

A198689 8*7^n-1.

Original entry on oeis.org

7, 55, 391, 2743, 19207, 134455, 941191, 6588343, 46118407, 322828855, 2259801991, 15818613943, 110730297607, 775112083255, 5425784582791, 37980492079543, 265863444556807, 1861044111897655, 13027308783283591, 91191161482985143
Offset: 0

Views

Author

Vincenzo Librandi, Oct 29 2011

Keywords

Crossrefs

Programs

  • Magma
    [8*7^n-1: n in [0..30]]

Formula

a(n) = 7*a(n-1)+6. a(n) = 8*a(n-1)-7*a(n-2), n>1.
G.f. ( 7-x ) / ( (7*x-1)*(x-1) ). - R. J. Mathar, Oct 30 2011

A198690 9*7^n-1.

Original entry on oeis.org

8, 62, 440, 3086, 21608, 151262, 1058840, 7411886, 51883208, 363182462, 2542277240, 17795940686, 124571584808, 872001093662, 6104007655640, 42728053589486, 299096375126408, 2093674625884862, 14655722381194040, 102590056668358286
Offset: 0

Views

Author

Vincenzo Librandi, Oct 29 2011

Keywords

Crossrefs

Programs

  • Magma
    [9*7^n-1: n in [0..30]]
  • Mathematica
    9*7^Range[0,30]-1 (* or *) LinearRecurrence[{8,-7},{8,62},30] (* Harvey P. Dale, Apr 22 2019 *)

Formula

a(n) = 7*a(n-1)+6. a(n) = 8*a(n-1)-7*a(n-2), n>1.
G.f. ( 8-2*x ) / ( (7*x-1)*(x-1) ). - R. J. Mathar, Oct 30 2011

A198691 10*7^n-1.

Original entry on oeis.org

9, 69, 489, 3429, 24009, 168069, 1176489, 8235429, 57648009, 403536069, 2824752489, 19773267429, 138412872009, 968890104069, 6782230728489, 47475615099429, 332329305696009, 2326305139872069, 16284135979104489, 113988951853731429
Offset: 0

Views

Author

Vincenzo Librandi, Oct 29 2011

Keywords

Crossrefs

Programs

  • Magma
    [10*7^n-1: n in [0..30]]
  • Mathematica
    10*7^Range[0,20]-1 (* or *) LinearRecurrence[{8,-7},{9,69},20] (* Harvey P. Dale, Mar 30 2016 *)

Formula

a(n) = 7*a(n-1)+6. a(n) = 8*a(n-1)-7*a(n-2), n>1.
G.f. ( 9-3*x ) / ( (7*x-1)*(x-1) ). - R. J. Mathar, Oct 30 2011

A198692 a(n) = 11*7^n-1.

Original entry on oeis.org

10, 76, 538, 3772, 26410, 184876, 1294138, 9058972, 63412810, 443889676, 3107227738, 21750594172, 152254159210, 1065779114476, 7460453801338, 52223176609372, 365562236265610, 2558935653859276, 17912549577014938
Offset: 0

Views

Author

Vincenzo Librandi, Oct 29 2011

Keywords

Crossrefs

Programs

  • Magma
    [11*7^n-1: n in [0..30]]
  • Mathematica
    11 (7^Range[0, 30]) - 1 (* Wesley Ivan Hurt, Jan 21 2017 *)

Formula

a(n) = 7*a(n-1)+6. a(n) = 8*a(n-1)-7*a(n-2), n>1.
G.f.: ( 10-4*x ) / ( (7*x-1)*(x-1) ). - R. J. Mathar, Oct 30 2011
Previous Showing 11-15 of 15 results.