123687

Appears in sequences

• Half the number of nXnXn triangular binary arrays with equal numbers of elements having four consecutive neighbors taken clockwise with value 1 and with value 0.at n=5A183281
• G.f. satisfies A(x) = A(x^2)/M(x), where M(x) = Sum_{n>=1} mu(n)*x^n and mu(n) = A008683(n), the Moebius function of n.at n=21A378260