OFFSET
0,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
MATHEMATICA
b:= Table[If[n<2, 1, Binomial[n, k] +3*Binomial[n-2, k-1]], {n, 0, 30}, {k, Floor[n/2]+1, n}]//Flatten;
Select[b, EvenQ]/2 (* G. C. Greubel, Jul 02 2024 *)
PROG
(Magma)
T:= func< n, k | n le 1 select 1 else Binomial(n, k) + 3*Binomial(n-2, k-1) >; // T = A028323
b:=[T(n, k): k in [1+Floor(n/2)..n], n in [0..100]];
[b[n]/2: n in [1..150] | (b[n] mod 2) eq 0]; // G. C. Greubel, Jul 02 2024
(SageMath)
def A028323(n, k): return binomial(n, k) + 3*binomial(n-2, k-1) - 3*int(n==0)
b=flatten([[A028323(n, k) for k in range(1+(n//2), n+1)] for n in range(101)])
[b[n]/2 for n in (1..150) if b[n]%2==0] # G. C. Greubel, Jul 02 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved