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 21-24 of 24 results.

A198768 a(n) = 9*5^n-1.

Original entry on oeis.org

8, 44, 224, 1124, 5624, 28124, 140624, 703124, 3515624, 17578124, 87890624, 439453124, 2197265624, 10986328124, 54931640624, 274658203124, 1373291015624, 6866455078124, 34332275390624, 171661376953124, 858306884765624
Offset: 0

Views

Author

Vincenzo Librandi, Oct 30 2011

Keywords

Crossrefs

Programs

  • Magma
    [9*5^n-1: n in [0..30]];
  • Mathematica
    9 5^Range[0, 20] - 1 (* or *) LinearRecurrence[{6, -5}, {8, 44}, 20] (* Harvey P. Dale, Nov 01 2011 *)
    CoefficientList[Series[(8 - 4 x)/(1 - 6 x + 5 x^2), {x, 0, 30}], x] (* Vincenzo Librandi, Jan 03 2013 *)

Formula

a(n) = 5*a(n-1)+4.
a(n) = 6*a(n-1)-5*a(n-2), n > 1.
G.f.: (8 - 4*x)/(1 - 6*x + 5*x^2). - Vincenzo Librandi, Jan 03 2013

A198769 a(n) = (9*5^n-1)/4.

Original entry on oeis.org

2, 11, 56, 281, 1406, 7031, 35156, 175781, 878906, 4394531, 21972656, 109863281, 549316406, 2746582031, 13732910156, 68664550781, 343322753906, 1716613769531, 8583068847656, 42915344238281, 214576721191406, 1072883605957031, 5364418029785156, 26822090148925781
Offset: 0

Views

Author

Vincenzo Librandi, Oct 30 2011

Keywords

Crossrefs

Programs

  • Magma
    [(9*5^n-1)/4: n in [0..30]];
  • Mathematica
    (9*5^Range[0,30]-1)/4 (* or *) LinearRecurrence[{6,-5},{2,11},30] (* Harvey P. Dale, May 07 2012 *)

Formula

a(n) = 5*a(n-1)+1.
a(n) = 6*a(n-1)-5*a(n-2), n>1.
G.f.: (2-x)/(5*x^2-6*x+1). - Harvey P. Dale, May 07 2012

A198770 11*5^n-1.

Original entry on oeis.org

10, 54, 274, 1374, 6874, 34374, 171874, 859374, 4296874, 21484374, 107421874, 537109374, 2685546874, 13427734374, 67138671874, 335693359374, 1678466796874, 8392333984374, 41961669921874, 209808349609374, 1049041748046874
Offset: 0

Views

Author

Vincenzo Librandi, Oct 30 2011

Keywords

Crossrefs

Programs

  • Magma
    [11*5^n-1: n in [0..30]];
  • Mathematica
    CoefficientList[Series[2*(5 - 3*x)/(1 - 6*x + 5*x^2), {x, 0, 30}], x] (* Vincenzo Librandi, Jan 04 2013 *)
    11*5^Range[0,20]-1 (* or *) LinearRecurrence[{6,-5},{10,54},30] (* Harvey P. Dale, May 14 2019 *)

Formula

a(n) = 5*a(n-1)+4.
a(n)= = 6*a(n-1)-5*a(n-2), n>1.
G.f.: 2*(5 - 3*x)/(1 - 6*x + 5*x^2). - Vincenzo Librandi, Jan 04 2013

A067763 Square array read by antidiagonals of base n numbers written as 122...222 with k 2's (and a suitable interpretation for n=0, 1 or 2).

Original entry on oeis.org

1, 2, 1, 2, 3, 1, 2, 5, 4, 1, 2, 7, 10, 5, 1, 2, 9, 22, 17, 6, 1, 2, 11, 46, 53, 26, 7, 1, 2, 13, 94, 161, 106, 37, 8, 1, 2, 15, 190, 485, 426, 187, 50, 9, 1, 2, 17, 382, 1457, 1706, 937, 302, 65, 10, 1, 2, 19, 766, 4373, 6826, 4687, 1814, 457, 82, 11, 1, 2, 21, 1534, 13121
Offset: 0

Views

Author

Henry Bottomley, Feb 06 2002

Keywords

Comments

Start with a node; step one is to connect that node to n+1 new nodes so that it is of degree n+1; further steps are to connect each existing node of degree 1 to n new nodes so that it is of degree n+1; T(n,k) is the total number of nodes after k steps.

Examples

			Rows start: 1,2,2,2,2,2,...; 1,3,5,7,9,11,...; 1,4,10,22,46,94,...; 1,5,17,53,161,485,... T(3,2) =122 base 3 =17.
		

Crossrefs

Rows include A040000, A005408, A033484, A048473, A020989, A057651, A061801 etc. For negative n (not shown) absolute values of rows would effectively include A000012, A014113, A046717.

Formula

T(n, k) =((n+1)*n^k-2)/(n-1) [with T(1, k)=2k+1] =n*T(n, k-1)+2 =(n+1)*T(n, k-1)-n*T(n, k-2) =T(n, k-1)+(1+1/n)*n^k =A055129(k, n)+A055129(k-1, n). Coefficient of x^k in expansion of (1+x)/((1-x)(1-nx)).
Previous Showing 21-24 of 24 results.