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A341576
a(n) = Sum_{k=0..n} U_k((n-k)/2) where U_n(x) is a Chebyshev polynomial of the 2nd kind.
2
1, 1, 1, 3, 7, 16, 46, 149, 520, 1977, 8136, 35878, 168501, 838945, 4409957, 24385913, 141412615, 857611640, 5426144190, 35739397739, 244573978100, 1735854397529, 12757309001220, 96941738970956, 760649367654461, 6155205917196409, 51308394497243469
OFFSET
0,4
MATHEMATICA
a[n_] := Sum[ChebyshevU[k, (n - k)/2], {k, 0, n}]; Array[a, 27, 0] (* Amiram Eldar, Mar 08 2021 *)
PROG
(PARI) a(n) = sum(k=0, n, polchebyshev(k, 2, (n-k)/2));
(Python)
from fractions import Fraction
from sympy import chebyshevu
def A341576(n): return sum(chebyshevu(k, Fraction(n-k, 2)) for k in range(n+1)) # Chai Wah Wu, Nov 08 2023
CROSSREFS
Sequence in context: A360782 A351821 A005312 * A143817 A297210 A000963
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 08 2021
STATUS
approved