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.

A091700 Matrix square of triangle A063967.

Original entry on oeis.org

1, 2, 1, 7, 6, 1, 23, 29, 10, 1, 78, 127, 67, 14, 1, 264, 527, 375, 121, 18, 1, 895, 2113, 1892, 831, 191, 22, 1, 3034, 8269, 8922, 4973, 1559, 277, 26, 1, 10286, 31781, 40115, 27139, 10826, 2623, 379, 30, 1, 34872, 120448, 174080, 138617, 67308, 20763, 4087, 497, 34, 1
Offset: 0

Views

Author

Christian G. Bower, Jan 29 2004

Keywords

Examples

			   1;
   2,   1;
   7,   6,  1;
  23,  29, 10,  1;
  78, 127, 67, 14, 1;
  ...
		

Crossrefs

Row sums: A091701.
Column 0: A091702.

A112973 Riordan array (1/(1-x-x^2), x(1+x)/(1-x-x^2)^2).

Original entry on oeis.org

1, 1, 1, 2, 4, 1, 3, 12, 7, 1, 5, 31, 31, 10, 1, 8, 73, 110, 59, 13, 1, 13, 162, 340, 267, 96, 16, 1, 21, 344, 956, 1022, 529, 142, 19, 1, 34, 707, 2507, 3479, 2416, 923, 197, 22, 1, 55, 1416, 6231, 10850, 9657, 4900, 1476, 261, 25, 1, 89, 2778, 14840, 31606, 34905
Offset: 0

Views

Author

Paul Barry, Oct 07 2005

Keywords

Comments

Row sums are A091702. Diagonal sums are A052960. First column is A000045(n+1).
Second column is A129707. - Ralf Stephan, Dec 31 2013

Examples

			Rows begin
1;
1,1;
2,4,1;
3,12,7,1;
5,31,31,10,1;
8,73,110,59,13,1;
		

Programs

  • Maxima
    T(n,k):=sum(binomial(m,n-m)*binomial(m+k,2*k),m,floor(n/2),n); /* Vladimir Kruchinin, Apr 21 2015 */

Formula

T(n,k) = 2*T(n-1,k) + T(n-1,k-1) + T(n-2,k) + T(n-2,k-1) - 2*T(n-3,k) - T(n-4,k), T(0,0) = T(1,0) = T(1,1) = T(2,2) = 1, T(2,0) = 2, T(2,1) = 4, T(n,k) = 0 if k<0 or if k>n. - Philippe Deléham, Jan 21 2014
G.f.: (x^2+x-1)/((x^2+x)*y-x^4-2*x^3+x^2+2*x-1). - Vladimir Kruchinin, Apr 21 2015
T(n,k) = Sum_{m=floor(n/2)..n} C(m,n-m)*C(m+k,2*k). - Vladimir Kruchinin, Apr 21 2015

Extensions

Definition corrected by Ralf Stephan, Dec 31 2013
Showing 1-2 of 2 results.