53228

Appears in sequences

• The next smallest pair of numbers is taken so that a(2n-1)/a(2n) converges to Pi.at n=38A057082
• Numerators of increasingly better rational approximations to Pi with increasing denominators (3/1, 13/4, 16/5, 19/6, 22/7, 179/57, ...)at n=17A063674
• a(n) = Sum_{k <= n/2 } binomial(n-2k, 3k).at n=23A137356
• Arises in enumerating non-degenerate colorings in Brook's Theorem.at n=13A152390
• Number of (n+2)X(n+2) 0..3 arrays with every consecutive three elements in every row and diagonal having exactly two distinct values, and in every column and antidiagonal not having exactly two distinct values, and new values 0 upwards introduced in row major order.at n=17A252711
• Number of compositions of 5*n-1 into parts 3 and 5.at n=13A369846
• a(n) = Sum_{k=0..floor((2*n+1)/3)} binomial(2*k+1,2*n-3*k+1).at n=16A391600