52290

Appears in sequences

• Fibonacci sequence beginning 2, 19.at n=18A022119
• s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = A023532, t = (Fibonacci numbers).at n=22A024367
• Number of matchings in the wheel graph with n spokes.at n=17A061705
• Composite numbers k such that the difference between the odd and even aliquot parts of k divides k.at n=29A066193
• Triangle T(n,k) (n >= 2, 2 <= k <= n-1 if n > 2) giving number of non-crossing trees with n nodes and k endpoints.at n=33A072247
• Amicable triples: numbers such that sigma(x) = sigma(y) = sigma(z) = x+y+z, x<y<z. We order these triples according to the common value of sigma. Sequence gives y numbers.at n=9A125491
• Quadruples a>b>c>d>0 such that six pairwise sums and the total sum are all squares.at n=17A175535
• Numbers k such that both the sum of the semiprime divisors of k and the sum of the prime divisors of k are squares.at n=7A227478
• The magic constants of most-perfect magic squares of order 6 composed of distinct prime numbers.at n=5A258755
• Number of ways to write n as an ordered sum of 7 primes (counting 1 as a prime).at n=31A341986
• Triangle T(n,k), n >= 0, 0 <= k <= n, read by rows, where T(n,k) = (-1)^k * [m^k] (1/2^(m-n)) * Sum_{k=0..m} k^n * (-1)^m * 3^(m-k) * binomial(m,k).at n=31A383149
• Expansion of e.g.f. -log(1 - (exp(2*x) - 1)/2)^3 / 6.at n=7A383164
• Numbers k for which sigma(k - x) + sigma(k + x) = 8*k has at least one nonnegative solution.at n=25A384841
• Primitive terms of A023197 that are of the form 4u+2.at n=35A388020