204204

Appears in sequences

• Expansion of 1/(1-4*x)^(7/2).at n=6A020918
• Expansion of (1-4*x)^(17/2).at n=6A020929
• a(n) = n^4 + n^3 + n^2 + n.at n=21A027445
• Array T(i,j) = binomial(-1/2-i,j)*(-4)^j, i,j >= 0 read by antidiagonals going down.at n=48A046521
• a(n) = (6n)!n!/((3n)!(2n)!^2).at n=3A061162
• Denominator of 2*Sum(C(n,w)/w,w=1..n/2-1)+C(n, n/2)/(n/2) if n is even otherwise of 2*Sum(C(n,w)/w,w=1..(n-1)/2).at n=33A085572
• a(n) = ((3*n)!/n!^2)*(Gamma(1+n/2)/Gamma(1+3n/2)).at n=6A091527
• Denominator of sum of all elements M(i,j,k) = i*j/k, (i,j,k = 1..n). a(n) = Denominator[Sum[Sum[Sum[i*j/k,{i,1,n}],{j,1,n}],{k,1,n}]].at n=18A099866
• Denominator of partial sums of a certain series.at n=3A101630
• Least non-palindromic number k such that k and its digital reversal both have exactly n prime divisors.at n=5A113548
• Triangle T(n,k) = lcm(1,...,2*n+2)/((k+1)*binomial(2*k+2,k+1)).at n=38A120101
• Number triangle T(n,k) = lcm(1,..,2*n+2)/lcm(1,..,2*k+2).at n=38A120105
• a(n) = Sum_{k=1..A124259(n)} n^k.at n=20A124260
• Expansion of (x^2)/(1-2*x-x^2+x^3)^2.at n=14A189426
• Smallest number m such that m and reverse(m) each have exactly n distinct prime factors.at n=5A239696
• Numbers x such that sigma(x)=sigma(T(x)), where sigma(x) is the sum of the divisors of x and T(x) the transform defined in A243993.at n=25A245468
• Triangle read by rows in which row(n) = {T(n, k)} is the lexicographically earliest list of n numbers such that adding 1 to some T(n, k) gives a row of numbers each divisible by prime(k).at n=23A286947
• a(n) = (9*n)!*n!/((5*n)!*(3*n)!*(2*n)!).at n=2A295441
• a(0) = 0, a(1) = 1 and a(n) = 6*a(n-1)/(n-1) + 4*a(n-2) for n > 1.at n=13A305032
• Number of (undirected) paths in the n-book graph.at n=36A307921