431910

Appears in sequences

• a(n) = 2^(2*n+1) - binomial(2*n+1, n+1).at n=9A000346
• Chvatal conjecture for radius of graph of maximal intersecting sets.at n=20A007008
• a(n) = Sum_{k=0..9} binomial(n,k).at n=20A008862
• a(n) = 2^n - binomial(n, floor(n/2)).at n=19A045621
• a(n) = 2^(n-1) - ((1+(-1)^n)/4)*binomial(n, n/2).at n=20A058622
• Riordan matrix (1/(1-4x),(1-sqrt(1-4x))/2).at n=56A187926
• Number of horizontal segments in all dispersed Dyck paths of length n (i.e., in all Motzkin paths of length n with no (1,0)-steps at positive heights; a horizontal segment is a maximal sequence of consecutive (1,0)-steps).at n=20A191391
• T(n,k)=Number of binary arrays of length n+2*k-1 with fewer than k ones in any length 2k subsequence (=less than 50% duty cycle).at n=45A213118
• Triangle read by rows: T(n,g) is the number of rooted maps with n edges and 2 faces on an orientable surface of genus g.at n=25A270406
• a(n) = 2^(n-1) + ((1+(-1)^n)/4)*binomial(n, n/2) - binomial(n, floor(n/2)).at n=20A294175