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 21-30 of 93 results. Next

A069382 Number of n X 7 binary arrays with a path of adjacent 1's from top row to bottom row.

Original entry on oeis.org

127, 14197, 1461797, 144769425, 14142942975, 1374273318721, 133267613878665, 12913642307413193, 1251002814214706415, 121180225103268487525, 11738064445690843712709, 1137001292953873957167377, 110135446775389136829629647, 10668293121854243285020490369
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 1 X n A000225, 2 X n A005061, n X 2 A001333, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Extensions

More terms from Sean A. Irvine, Apr 30 2024

A069383 Number of n X 8 binary arrays with a path of adjacent 1's from top row to bottom row.

Original entry on oeis.org

255, 58975, 12519345, 2541013617, 506544513343, 100193001007135, 19752116290408897, 3888492110032895921, 765068584835726823447, 150495460332124702700743, 29601436900513534956486417, 5822276945638780019957186657, 1145175890285973091225709069559
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 1 X n A000225, 2 X n A005061, n X 2 A001333, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Extensions

More terms from Sean A. Irvine, Apr 30 2024

A069384 Number of n X 9 binary arrays with a path of adjacent 1's from top row to bottom row.

Original entry on oeis.org

511, 242461, 105683341, 43843180113, 17792504911231, 7146486319870849, 2856738227918860537, 1139431807812280823353, 454016084146597129480639, 180827014727915133583355805, 72007238386097441302774324845, 28672084199736350940864453233905
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 1 X n A000225, 2 X n A005061, n X 2 A001333, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Extensions

More terms from Sean A. Irvine, Apr 30 2024

A069385 Number of n X 10 binary arrays with a path of adjacent 1's from top row to bottom row.

Original entry on oeis.org

1023, 989527, 882516857, 746691527217, 615793150236223, 501394148790682463, 405671453894948801169, 327195886636045773364289, 263496356226918378172858791, 212041997127527144580159558415, 170577316159214009818521435822905, 137200626549758017615769211506956897
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 1 X n A000225, 2 X n A005061, n X 2 A001333, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Extensions

More terms from Sean A. Irvine, Apr 30 2024

A069386 Number of n X 11 binary arrays with a path of adjacent 1's from top row to bottom row.

Original entry on oeis.org

2047, 4017157, 7308428597, 12588144461329, 21067276157958271, 34728307983514473409, 56797093221062281961353, 92506527736225809457497129, 150343681421865609328377897039, 244072929303780515911965529991989, 396017759826921556057184566557279157
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 1 X n A000225, 2 X n A005061, n X 2 A001333, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Extensions

More terms from Sean A. Irvine, Apr 30 2024

A069387 Number of n X 12 binary arrays with a path of adjacent 1's from top row to bottom row.

Original entry on oeis.org

4095, 16245775, 60131384705, 210502738714097, 714097521397778495, 2380826437768134741023, 7862987107940658832635809, 25834416752721407468468718385, 84641600245355780352751022513463, 276889755885138056467643815501003447, 905061607197623234620822097612564300097
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 1 X n A000225, 2 X n A005061, n X 2 A001333, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Extensions

More terms from Sean A. Irvine, Apr 30 2024

A337129 Triangular array read by rows: T(n,0) = 2^n, T(n,k) = Sum_{i=n-k..n, j=0..i-n+k, i<>n or j<>k} T(i,j) for k > 0.

Original entry on oeis.org

1, 2, 3, 4, 6, 16, 8, 12, 32, 84, 16, 24, 64, 168, 440, 32, 48, 128, 336, 880, 2304, 64, 96, 256, 672, 1760, 4608, 12064, 128, 192, 512, 1344, 3520, 9216, 24128, 63168, 256, 384, 1024, 2688, 7040, 18432, 48256, 126336, 330752, 512, 768, 2048, 5376, 14080, 36864, 96512, 252672, 661504, 1731840
Offset: 0

Views

Author

Oboifeng Dira, Sep 14 2020

Keywords

Examples

			The triangle  T(n,k) begins:
   n\k  0    1    2    3    4    5
   0:   1
   1:   2    3
   2:   4    6    16
   3:   8    12   32  84
   4:   16   24   64  168  440
   5:   32   48   128 336  880  2304
   ...
T(3,2) = ((3+sqrt(5))^3-(3-sqrt(5))^3)*(2)/(4*sqrt(5)) = (64*sqrt(5))/(2*sqrt(5)) = 32.
		

Crossrefs

Cf. A000079 (1st column), A069429 (diagonal), A018903 (row sums), A001906, A004171.

Programs

  • Maple
    T := proc (n, k) if k = 0 and 0 <= n then 2^n elif 1 <= k and k <= n then round((((3+sqrt(5))^(k+1)-(3-sqrt(5))^(k+1))*(2^(n-k))/(4*sqrt(5)))) else 0 end if end proc:seq(print(seq(T(n, k), k=0..n)), n=0..9);
  • Mathematica
    T[n_, 0] := 2^n;
    T[n_, n_] := 2^(n-1) Fibonacci[2n+2];
    T[n_, k_] /; 0Jean-François Alcover, Nov 13 2020 *)
  • PARI
    T(n,k) = if (k == 0, 2^n, my(w=quadgen(5, 'w)); ((2*w+2)^(k+1)-(4-2*w)^(k+1))*(2^(n-k))/(4*(2*w-1))); \\ Michel Marcus, Sep 14 2020
    
  • PARI
    Row(n)={Vecrev(polcoef((1-x*y)*(1-2*x*y)/((1-6*x*y+4*x^2*y^2)*(1-2*x)) + O(x*x^n), n))} \\ Andrew Howroyd, Sep 23 2020

Formula

T(n,0) = 2^n.
T(n,k) = ((3+sqrt(5))^(k+1)-(3-sqrt(5))^(k+1))*(2^(n-k))/(4*sqrt(5)) for 1<=k<=n.
T(n+1,n) = 2*T(n,n).
T(n+m,n) = 2^m*T(n,n), for m>=1.
T(n,n) = A069429(n) = 2^(n-1)*A001906(n+1) for n>=1.
T(2*n,n) = (1/2)*A099157(n+1) = A004171(n-1)*A001906(n+1) for n>=1.
G.f.: (1 - x*y)*(1 - 2*x*y)/((1 - 6*x*y + 4*x^2*y^2)*(1 - 2*x)). - Andrew Howroyd, Sep 23 2020

A069364 Number of 6 X n binary arrays with a path of adjacent 1's from top row to bottom row.

Original entry on oeis.org

1, 239, 29089, 2764991, 232824241, 18287614751, 1374273318721, 100193001007135, 7146486319870849, 501394148790682463, 34728307983514473409, 2380826437768134741023, 161857825276476548906497
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 1 X n A000225, 2 X n A005061, n X 2 A001333, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Extensions

a(9)-a(13) from Sean A. Irvine, Apr 29 2024

A069365 Number of 7 X n binary arrays with a path of adjacent 1's from top row to bottom row.

Original entry on oeis.org

1, 577, 153769, 30856705, 5388274121, 868972410929, 133267613878665, 19752116290408897, 2856738227918860537, 405671453894948801169, 56797093221062281961353, 7862987107940658832635809, 1078636993747832299068001753
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 1 X n A000225, 2 X n A005061, n X 2 A001333, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Extensions

a(7)-a(13) from Sean A. Irvine, Apr 29 2024

A069366 Number of 8 X n binary arrays with a path of adjacent 1's from top row to bottom row.

Original entry on oeis.org

1, 1393, 812849, 344356289, 124693133113, 41278350729313, 12913642307413193, 3888492110032895921, 1139431807812280823353, 327195886636045773364289, 92506527736225809457497129, 25834416752721407468468718385, 7143459701634079128687197933529
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 1 X n A000225, 2 X n A005061, n X 2 A001333, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Extensions

a(7)-a(13) from Sean A. Irvine, Apr 29 2024
Previous Showing 21-30 of 93 results. Next