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 1-3 of 3 results.

A190089 Row sums of the triangular matrix A190088.

Original entry on oeis.org

1, 4, 21, 114, 616, 3329, 17991, 97229, 525456, 2839729, 15346786, 82938844, 448227521, 2422362079, 13091204281, 70748973084, 382349636061, 2066337330754, 11167134898976, 60350698792449, 326154101090951, 1762639037938629, 9525854090667496, 51480702630305689, 278217860370802066
Offset: 0

Views

Author

Emanuele Munarini, May 04 2011

Keywords

Crossrefs

Programs

  • Magma
    [(&+[Binomial(3*n-k+1,3*n-3*k+1): k in [0..n]]): n in [0..30]]; // G. C. Greubel, Mar 04 2018
  • Mathematica
    Table[Sum[Binomial[3n - k + 1, 3n - 3k + 1], {k, 0, n}], {n, 0, 12}]
    LinearRecurrence[{5,2,1},{1,4,21},30] (* Harvey P. Dale, Sep 18 2013 *)
  • Maxima
    makelist(sum(binomial(3*n-k+1,3*n-3*k+1),k,0,n),n,0,24);
    
  • PARI
    Vec((1-x-x^2)/(1-5*x-2*x^2-x^3)+O(x^99)) \\ Charles R Greathouse IV, Jun 30 2011
    

Formula

a(n) = Sum_{k=0..n} binomial(3*n-k+1,3*n-3*k+1).
G.f.: (1-x-x^2)/(1-5*x-2*x^2-x^3).
a(n) = 5*a(n-1)+2*a(n-2)+a(n-3) and a(0)=1, a(1)=4, a(2)=21. - Harvey P. Dale, Sep 18 2013

A190090 Diagonal sums of the triangular matrix A190088.

Original entry on oeis.org

1, 1, 4, 16, 42, 137, 443, 1365, 4316, 13625, 42785, 134758, 424331, 1335378, 4203927, 13233947, 41657808, 131135696, 412803240, 1299458257, 4090567673, 12876698159, 40534529294, 127598621869, 401667591501, 1264408966284, 3980231826575, 12529367967276, 39441185140197
Offset: 0

Views

Author

Emanuele Munarini, May 04 2011

Keywords

Crossrefs

Programs

  • Magma
    [(&+[Binomial(3*n-4*k+1,3*n-6*k+1): k in [0..Floor(n/2)]]): n in [0..30]]; // G. C. Greubel, Mar 04 2018
  • Mathematica
    Table[Sum[Binomial[3n - 4k + 1, 3n - 6k + 1], {k, 0, n/2}], {n, 0, 26}]
    LinearRecurrence[{2,2,6,-3,0,1},{1,1,4,16,42,137},27] (* Harvey P. Dale, Jul 04 2011 *)
  • Maxima
    makelist(sum(binomial(3*n-4*k+1,3*n-6*k+1),k,0,n/2),n,0,12);
    
  • PARI
    Vec((1-x-x^4)/(1-2*x-2*x^2-6*x^3+3*x^4-x^6)+O(x^29)) \\ Charles R Greathouse IV, Jun 30 2011
    

Formula

a(n) = Sum_{k=0..floor(n/2)} binomial(3*n-4*k+1,3*n-6*k+1).
G.f.: (1-x-x^4)/(1-2*x-2*x^2-6*x^3+3*x^4-x^6).
a(n) = 2*a(n-1)+ 2*a(n-2)+ 6*a(n-3)-3*a(n-4)+a(n-6), and a(0)=1, a(1)=1, a(2)=4, a(3)=16, a(4)=42, a(5)=137, . - Harvey P. Dale, Jul 04 2011

A190152 Triangle of binomial coefficients binomial(3*n-k,3*n-3*k).

Original entry on oeis.org

1, 1, 1, 1, 10, 1, 1, 28, 35, 1, 1, 55, 210, 84, 1, 1, 91, 715, 924, 165, 1, 1, 136, 1820, 5005, 3003, 286, 1, 1, 190, 3876, 18564, 24310, 8008, 455, 1, 1, 253, 7315, 54264, 125970, 92378, 18564, 680, 1, 1, 325, 12650, 134596, 490314, 646646, 293930, 38760, 969, 1
Offset: 0

Views

Author

Emanuele Munarini, May 05 2011

Keywords

Comments

From R. J. Mathar, Mar 15 2013: (Start)
The matrix inverse starts
1;
-1,1;
9,-10,1;
-288,322,-35,1;
22356,-25003,2730,-84,1;
-3428973,3835026,-418825,12936,-165,1;
914976405,-1023326973,111759115,-3452449,44187,-286,1;
... (End)

Examples

			Triangle begins:
  1
  1, 1
  1, 10, 1
  1, 28, 35, 1
  1, 55, 210, 84, 1
  1, 91, 715, 924, 165, 1
  1, 136, 1820, 5005, 3003, 286, 1
  1, 190, 3876, 18564, 24310, 8008, 455, 1
  1, 253, 7315, 54264, 125970, 92378, 18564, 680, 1
  ...
		

Crossrefs

Cf. A000447 (first subdiagonal), A053135 (second subdiagonal), A060544 (second column), A190088, A190153 (row sums), A190154 (diagonal sums).

Programs

  • Mathematica
    Flatten[Table[Binomial[3n - k, 3n - 3k], {n, 0, 9}, {k, 0, n}]]
  • Maxima
    create_list(binomial(3*n-k,3*n-3*k),n,0,9,k,0,n);
    
  • PARI
    for(n=0,10, for(k=0,n, print1(binomial(3*n-k, 3*(n-k)), ", "))) \\ G. C. Greubel, Dec 29 2017
Showing 1-3 of 3 results.