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.

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A158524 Choulet-Curtz triangle with T(0,0)=1, T(n,n)=T(n,0).

Original entry on oeis.org

1, 1, 1, 2, 2, 2, 6, 3, 3, 6, 18, 4, 4, 8, 18, 52, 5, 5, 10, 24, 52, 148, 6, 6, 12, 30, 70, 148, 420, 7, 7, 14, 36, 88, 200, 420, 1192, 8, 8, 16, 42, 106, 252, 568, 1192, 3384, 9, 9, 18, 48, 124, 304, 716, 1612, 3384, 9608, 10, 10, 20, 54, 142, 356, 864, 2032, 4576, 9608
Offset: 0

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Author

Philippe Deléham, Mar 20 2009

Keywords

Comments

Row sums are in A078484.
This sequence is an example of a sequence u(n) which satisfies (using the notation from the link): T_{1,1}(u(0), u(1), u(2), u(3), ...) = (u(1), u(2), u(3), ...). The o.g.f of all such sequences is given by the formula Phi(z)=u(0)*((1-3*z+2*z^2-z^3)/(1-4*z+4*z^2-2*z^3))+((z+z^3)/(1-4*z+4*z^2-2*z^3)) with u(0) in N or Z; the sequences are given by u(n) = u(0)*(1, 1, 2, 5, 14, 40, 114, 324, 920, ...) + (0, 1, 4, 13, 38, 108, 868, 2464, 6996, ...), i.e., u(n) = u(0)*A159035(n) + A159036(n). - Richard Choulet, Apr 03 2009

Examples

			Triangle begins
    1;
    1,   1;
    2,   2,   2;
    6,   3,   3,   6;
   18,   4,   4,   8,  18;
   52,   5,   5,  10,  24,  52;
  148,   6,   6,  12,  30,  70, 148;
		

Crossrefs

Cf. A078484.
Cf. A159035, A159036. - Richard Choulet, Apr 03 2009

Formula

T(n,k) = T(n-1,k) + T(k-1,k-1), k >= 1, n > k;
T(n,n) = T(n,0) = Sum_{k=0..n} T(n-1,k); T(0,0)=1.
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