OFFSET
0,4
COMMENTS
Odd elements of A028323. - G. C. Greubel, Jan 06 2024
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
MATHEMATICA
A028313[n_, k_]:= If[n<2, 1, Binomial[n, k] + 3*Binomial[n-2, k-1]];
f= Table[A028313[n, k], {n, 0, 100}, {k, 1+Floor[n/2], n}]//Flatten;
b[n_]:= DeleteCases[{f[[n+1]]}, _?EvenQ];
Table[b[n], {n, 0, 150}]//Flatten (* G. C. Greubel, Jan 06 2024 *)
PROG
(Magma)
T:= func< n, k | Binomial(n+1, k+1+Floor((n+1)/2)) + 3*Binomial(n-1, k+Floor((n+1)/2)) >; // T = A028323, essentially
b:=[T(n, k): k in [0..Floor(n/2)], n in [0..100]];
[b[n]: n in [1..150] | (b[n] mod 2) eq 1]; // G. C. Greubel, Jan 06 2024
(SageMath)
def T(n, k): return binomial(n+1, k+1+(n+1)//2) + 3*binomial(n-1, k+((n+1)//2)) - 3*int(n==0) # T = A028323, essentially
b=flatten([[T(n, k) for k in range(1+(n//2))] for n in range(101)])
[b[n] for n in (1..150) if b[n]%2==1] # G. C. Greubel, Jan 06 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from James A. Sellers
STATUS
approved