OFFSET
0,4
COMMENTS
Run length transform of the coefficients of (1-2x^3)/(1-x-x^2), i.e., 1, 1, 2, 1, 3, 4, 7, 11, ... (1, 1 followed by the Lucas sequence A000032).
LINKS
Chai Wah Wu, Table of n, a(n) for n = 0..10000
Chai Wah Wu, Sums of products of binomial coefficients mod 2 and run length transforms of sequences, arXiv:1610.06166 [math.CO], 2016.
PROG
(PARI) a(n) = sum(k=0, n, lift(Mod((binomial(n+2*k, 2*n-k)*binomial(n, k)), 2))) \\ Felix Fröhlich, Nov 25 2019
(Python)
def A329722(n): return sum(int(not (~(n+2*k) & 2*n-k) | (~n & k)) for k in range(n+1)) # Chai Wah Wu, Sep 28 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Chai Wah Wu, Nov 19 2019
STATUS
approved