654729075

Appears in sequences

• Double factorial of odd numbers: a(n) = (2*n-1)!! = 1*3*5*...*(2*n-1).at n=10A001147
• Double factorials n!!: a(n) = n*a(n-2) for n > 1, a(0) = a(1) = 1.at n=19A006882
• 2-adic factorial function.at n=20A055634
• Volume of n-dimensional sphere of radius r is V_n*r^n = Pi^(n/2)*r^n/(n/2)! = C_n*Pi^floor(n/2)*r^n; sequence gives denominator of C_n.at n=19A072346
• Surface area of n-dimensional sphere of radius r is n*V_n*r^(n-1) = n*Pi^(n/2)*r^(n-1)/(n/2)! = S_n*Pi^floor(n/2)*r^(n-1); sequence gives denominator of S_n.at n=21A072479
• a(n) = (n+1)*a(n-2) with a(0) = a(1) = 1.at n=18A081405
• Double factorial of primes.at n=7A091835
• a(n) = (4n)! / ( 4^n * (2n)! ).at n=5A101485
• Square of P(n,t) read by antidiagonals. P(n,t) = number of ways to split [t*n] into n arithmetic progressions each with t terms.at n=64A104443
• Oddly superabundant numbers: odd n with sigma(n)/n > sigma(k)/k for all odd k < n.at n=29A119239
• a(n) = (n-1)*a(n-2), a(0)=1, a(1)=0.at n=20A123023
• Q(1,n), where Q(m,k) is defined in A127080 and A127137.at n=20A127138
• A001147 with each term repeated.at n=21A133221
• A001147 with each term repeated.at n=20A133221
• Triangle of numbers obtained from the partition array A134145.at n=45A134146
• Smallest odd number with same number of divisors as 3*a(n-1).at n=22A140864
• List of pairs of numbers: {n^2-1, (2*n-1)!!} such that F((2*n-1)!!) = n^2 - 1.at n=19A154029
• Triangular sequence from coefficients of the polynomial recursion: p(x,n)=Sum[Binomial[n, m]*p[x, m]*p[x, n - m - 1], {m, 0, n - 1}].at n=35A157526
• Triangle read by rows: T(n,k) (1 <= k <= n-1, n >= 2) = d(2*(n-k)-1)*(d(2*n-2)/d(2*(n-k)-2) - d(2*n-3)/d(2*(n-k)-3)), where d = A006882 is the double factorial function.at n=45A202212
• Number of words w where each letter of the 10-ary alphabet occurs n times and for every prefix z of w we have #(z,a_i) = 0 or #(z,a_i) >= #(z,a_j) for all j>i and #(z,a_i) counts the occurrences of the i-th letter in z.at n=2A213872