login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A322836 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where A(n,k) is Chebyshev polynomial of the first kind T_{n}(x), evaluated at x=k. 10
1, 1, 0, 1, 1, -1, 1, 2, 1, 0, 1, 3, 7, 1, 1, 1, 4, 17, 26, 1, 0, 1, 5, 31, 99, 97, 1, -1, 1, 6, 49, 244, 577, 362, 1, 0, 1, 7, 71, 485, 1921, 3363, 1351, 1, 1, 1, 8, 97, 846, 4801, 15124, 19601, 5042, 1, 0, 1, 9, 127, 1351, 10081, 47525, 119071, 114243, 18817, 1, -1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,8
LINKS
FORMULA
A(0,k) = 1, A(1,k) = k and A(n,k) = 2 * k * A(n-1,k) - A(n-2,k) for n > 1.
A(n,k) = cos(n*arccos(k)). - Seiichi Manyama, Mar 05 2021
A(n,k) = n * Sum_{j=0..n} (2*k-2)^j * binomial(n+j,2*j)/(n+j) for n > 0. - Seiichi Manyama, Mar 05 2021
EXAMPLE
Square array begins:
1, 1, 1, 1, 1, 1, 1, ...
0, 1, 2, 3, 4, 5, 6, ...
-1, 1, 7, 17, 31, 49, 71, ...
0, 1, 26, 99, 244, 485, 846, ...
1, 1, 97, 577, 1921, 4801, 10081, ...
0, 1, 362, 3363, 15124, 47525, 120126, ...
-1, 1, 1351, 19601, 119071, 470449, 1431431, ...
MATHEMATICA
Table[ChebyshevT[n-k, k], {n, 0, 10}, {k, n, 0, -1}] // Flatten (* Amiram Eldar, Dec 28 2018 *)
PROG
(PARI) T(n, k) = polchebyshev(n, 1, k);
matrix(7, 7, n, k, T(n-1, k-1)) \\ Michel Marcus, Dec 28 2018
(PARI) T(n, k) = round(cos(n*acos(k))); \\ Seiichi Manyama, Mar 05 2021
(PARI) T(n, k) = if(n==0, 1, n*sum(j=0, n, (2*k-2)^j*binomial(n+j, 2*j)/(n+j))); \\ Seiichi Manyama, Mar 05 2021
CROSSREFS
Mirror of A101124.
Main diagonal gives A115066.
Cf. A323182 (Chebyshev polynomial of the second kind).
Sequence in context: A210472 A320080 A246106 * A305466 A160114 A213028
KEYWORD
sign,tabl
AUTHOR
Seiichi Manyama, Dec 28 2018
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 30 14:49 EDT 2024. Contains 372134 sequences. (Running on oeis4.)