A107238 A Chebyshev transform of number triangle A107230.

1, 1, 1, 0, 2, 1, 0, 3, 3, 1, 0, 4, 8, 4, 1, 0, 5, 15, 15, 5, 1, 0, 6, 27, 36, 24, 6, 1, 0, 7, 42, 84, 70, 35, 7, 1, 0, 8, 64, 160, 200, 120, 48, 8, 1, 0, 9, 90, 300, 450, 405, 189, 63, 9, 1, 0, 10, 125, 500, 1000, 1050, 735, 280, 80, 10, 1, 0, 11, 165, 825, 1925, 2695, 2156, 1232, 396

Offset

0,5

Comments

Product of the number triangle A107230 by the Riordan array ((1-x^2)/(1+x^2),x/(1+x^2)). First column if C(1,n), second column is n (A001477), third column is essentially A034828.

Links

Table of n, a(n) for n=0..74.

Formula

Number triangle T(n, k)=sum{j=0..floor(n/2), (n/(n-j))(-1)^j*C(n-j, j)*A107230(n-2j, k)} (with T(0, n)=0^n).

Example

Triangle begins
1;
1,1;
0,2,1;
0,3,3,1;
0,4,8,4,1;
0,5,15,15,5,1;

Crossrefs

Sequence in context: A206735 A089000 A253829 * A258170 A055830 A293109

Adjacent sequences: A107235 A107236 A107237 * A107239 A107240 A107241

Keyword

easy,nonn,tabl

Author

Paul Barry, May 14 2005

Status

approved