117950

Appears in sequences

• First subdiagonal of triangular array T: T(j,1) = 1 for ((j-1) mod 6) < 3, else 0; T(j,k) = T(j-1,k-1) + T(j-1,k) for 2 <= k <= j.at n=18A131023
• a(n) = 2*a(n-1)+3*a(n-2)-6*a(n-3) starting a(0)=a(1)=0, a(2)=1.at n=17A167762
• a(n) = 2^n - (1 - (-1)^n)*3^((n-1)/2).at n=17A167784
• Number of subsets of {1..n} containing two distinct elements summing to n.at n=17A365544
• Number of subsets of {1..n} with two elements (possibly the same) summing to n.at n=17A366131