A101125 Row sums of a Chebyshev number triangle.

1, 1, 1, 4, 13, 49, 233, 1240, 7201, 45521, 311225, 2285116, 17909309, 149080865, 1312597361, 12180044528, 118740086369, 1212695223137, 12942512039697, 144018843991220, 1667526171728525, 20053044685823697, 250043383489271193

Offset

0,4

Comments

Row sums of A101124.

Links

Seiichi Manyama, Table of n, a(n) for n = 0..533

Index entries for sequences related to Chebyshev polynomials.

Formula

a(n)=sum{k=0..n, if(k<n, T(n-k, k), if(k=n, 1, 0))} where T(n, k)=(n/2)sum{j=0..floor(n/2), C(n-j, j)(-1)^j*(2k)^(n-2j)}.

Mathematica

Table[Sum[ChebyshevT[k, n-k], {k, 0, n}], {n, 0, 30}] (* Vaclav Kotesovec, Jan 20 2019 *)

Prog

(PARI) {a(n) = sum(k=0, n, polchebyshev(k, 1, n-k))} \\ Seiichi Manyama, Jan 20 2019

Crossrefs

Sequence in context: A140660 A149453 A149454 * A284336 A230081 A364907

Adjacent sequences: A101122 A101123 A101124 * A101126 A101127 A101128

Keyword

easy,nonn

Author

Paul Barry, Dec 02 2004

Status

approved