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A329720
a(n) = Sum_{k=0..n} ((binomial(n-k,6k)*binomial(n,k)) mod 2).
1
1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 3, 4, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 4, 6, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2
OFFSET
0,8
COMMENTS
Run length transform of Narayana's cows sequence (A000930).
PROG
(PARI) a(n) = sum(k=0, n, (binomial(n-k, 6*k)*binomial(n, k)) % 2); \\ Michel Marcus, Feb 08 2020
(Python)
def A329720(n): return sum(int(not (~(n-k) & 6*k) | (~n & k)) for k in range(n+1)) # Chai Wah Wu, Sep 28 2021
CROSSREFS
Cf. A000930.
Sequence in context: A242217 A306734 A124060 * A140194 A353282 A350714
KEYWORD
nonn
AUTHOR
Chai Wah Wu, Nov 19 2019
STATUS
approved