97240

Appears in sequences

• a(1)=1; for n >= 1, a(n+1) = lcm(a(n),n) / gcd(a(n),n).at n=17A008339
• Expansion of (1-4*x)^(19/2).at n=19A020931
• Twice central binomial coefficients.at n=9A028329
• First numerator and then denominator of the central elements of the 1/5-Pascal triangle (by row).at n=20A046610
• First denominator and then numerator of the central elements of the 1/5-Pascal triangle (by row).at n=21A046611
• Distinct numbers in writing first numerator and then denominator of the central elements of the 1/5-Pascal triangle (by row).at n=10A046612
• a(n) = Sum_{j=0..n} A047072(j, n-j).at n=19A047073
• a(n) = (n+3)*binomial(n+8, 8)/3.at n=9A053310
• 4-wave sequence beginning with 2's with middles dropped.at n=11A060823
• 4-wave sequence beginning with 2s.at n=33A060824
• Number of n-step walks on a line starting from the origin but not returning to it.at n=19A063886
• a(1) = 1, a(n) = lcm(n, a(n-1)) / gcd(n, a(n-1)).at n=16A077139
• Tenth column (m=9) of (1,3)-Pascal triangle A095660.at n=9A095665
• A Catalan transform of (1 + 2*x)/(1 - 2*x).at n=9A100320
• Heights of right triangles that are solutions to Leech's problem A117319.at n=42A117321
• Triangle read by rows: T(n,k) is the number of Grand Dyck paths of semilength n having first return to the x-axis at (2k,0) (n,k >= 1). (A Grand Dyck path of semilength n is a path in the half-plane x >= 0, starting at (0,0), ending at (2n,0) and consisting of steps u=(1,1) and d=(1,-1)).at n=45A118921
• A triangle of coefficients: T(n,m) = (2*n + 2*m + 3)! / (2*(2*m + 1)!*(2*n + 1)!).at n=13A143083
• Minimal covering numbers.at n=44A160559
• a(n) = number of n-lettered words in the alphabet {1, 2} with as many occurrences of the substring (consecutive subword) [1, 1] as of [2, 2].at n=20A182027
• Number of compositions of odd natural numbers into 4 parts <= n.at n=20A191903