21518

Appears in sequences

• Number of graphical partitions (degree-vectors for graphs with n vertices, allowing self-loops which count as degree 1; or possible ordered row-sum vectors for a symmetric 0-1 matrix).at n=9A029889
• Sequence relating to the benzene ring.at n=11A120262
• Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and column sum 2 4 5 or 7 and every diagonal and antidiagonal sum not 2 4 5 or 7.at n=7A251916
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum 2 4 5 or 7 and every diagonal and antidiagonal sum not 2 4 5 or 7.at n=28A251923
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum 2 4 5 or 7 and every diagonal and antidiagonal sum not 2 4 5 or 7.at n=35A251923
• Number of compositions of n such that the maximal distance between two identical parts equals four.at n=16A262197
• a(n) = n*(2*n - 3 - (-1)^n)*(11*n + (-1)^n)/24.at n=28A308026
• Number of ways to reach n by starting with 1 and repeatedly adding any positive integer or multiplying by any integer greater than 1.at n=14A348396
• Zero-avoiding Fibonacci sequence: a(n) is the largest zeroless number that can be written as a(i) + a(j) where 1 <= i < j < n with a(1) = a(2) = 1.at n=22A374924
• Numbers k whose binary expansion contains 2 adjacent 1's and A391571(k) = k.at n=43A391581