484922
domain: N
Appears in sequences
- Main diagonal 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,k-1) for 2 <= k <= j.at n=20A129339
- 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=19A167762
- a(n) = 2^n - (1 - (-1)^n)*3^((n-1)/2).at n=19A167784
- Number of subsets of {1..n} containing two distinct elements summing to n.at n=19A365544
- Number of subsets of {1..n} with two elements (possibly the same) summing to n.at n=19A366131