364416

Appears in sequences

• Janet periodic table of the elements and structured hexagonal diamond numbers. a(n) = A166911(2*n) + A166911(2*n+1).at n=25A167471
• a(n) = Sum_{k=0..floor((n-1)/2)} (3^k-1)*binomial(n, 2*k+1).at n=11A176758