20042

Appears in sequences

• 2*Sum(floor(C(n,w)/w),w=1..n/2-1)+floor(C(n,n/2)/(n/2)) if n is even, otherwise 2*Sum(floor(C(n,w)/w),w=1..(n-1)/2).at n=15A085573
• Number of triangular partitions of n.at n=30A089647
• Triangle read by rows: T(n,k) is the number of ordered trees with n edges and having k branches of even length (n>=0, 0<=k<=floor(n/2)).at n=42A102004
• Triangle read by rows: T(n,k) is the number of skew Dyck paths of semilength n and having k UUU's (triplerises) (n >= 0; 0 <= k <= n-2 for n >= 2).at n=47A128719
• Number of paths in the first quadrant from (0,0) to (n,0) using steps U=(1,1), D=(1,-1), h=(1,0) and H=(2,0).at n=11A128720
• Numbers k such that (26*10^k - 23)/3 is prime.at n=25A276046
• Numbers k such that 303*2^k+1 is prime.at n=38A322916
• Number of compositions (ordered partitions) of n into distinct parts, the least being 1.at n=28A339162
• Consecutive internal states of the linear congruential pseudo-random number generator (421*s + 54773) mod 259200 when started at 1.at n=17A383129