31078

Appears in sequences

• Numbers k such that 201*2^k-1 is prime.at n=42A050852
• A generalized Narayana triangle for sec(x)^2.at n=40A180960
• Number of ways to arrange 2 nonattacking knights on the lower triangle of an n X n board.at n=21A194486
• Number of (n+2)X(n+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00000011 or 00001011.at n=5A260493
• Number of (n+2)X(6+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00000011 or 00001011.at n=5A260499
• Number of compositions of 7*n into parts 5 and 7.at n=15A373911
• a(n) = Sum_{k=0..floor(2*n/5)} binomial(2*k+1,2*n-5*k).at n=25A392455