18354

Appears in sequences

• Otto Haxel's guess for magic numbers of nuclear shells.at n=38A033547
• a(n) = binomial(n,2) * !n.at n=7A061834
• Least area of primitive Pythagorean triangle whose legs differ by A058529(n).at n=40A094143
• Consider a Pythagorean triangle with sides a=u^2-v^2, b=2uv, c=u^2+v^2. The sequence is the area of the triangle when v=2, u=3,4,5,...at n=18A096382
• Numbers k such that the central binomial coefficient C(2k,k) is divisible by k^2.at n=32A121943
• A Moessner triangle using (1, 3, 5, ...).at n=42A125750
• a(n) = largest value of the function rad(m*n*(n - m)) n=2,3,4,..., 0 < m < n where the function rad(k) (also called radical(k)) is the product of distinct prime divisors of k.at n=40A147299
• Squarefree positive integers of the form u*v*(u^2-v^2) for some integer u,v.at n=18A147779
• If 0 <= n <= 3 then a(n) = n(n+1)(n+2)/3, if n >= 4 then a(n) = n(n^2+5)/3.at n=38A162626
• a(n) = (n+6)*(n+1)*(n^2 + 7*n + 16)/4.at n=14A168538
• Number of n X n 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 1,3,2,4,0 for x=0,1,2,3,4.at n=5A196916
• Number of nX6 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 1,3,2,4,0 for x=0,1,2,3,4.at n=5A196920
• T(n,k)=Number of nXk 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 1,3,2,4,0 for x=0,1,2,3,4.at n=60A196922
• Triangular array read by rows: T(n,k) is the number of ways to partition an n-set into exactly k blocks and then partially order the blocks, n>=1, 1<=k<=n.at n=30A247231
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 267", based on the 5-celled von Neumann neighborhood.at n=29A271085
• Numbers k such that (13*10^k + 437)/9 is prime.at n=19A282351
• Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n)^2, where a(0) = 1, a(1) = 2, b(0) = 3, b(1) = 4, b(2) = 5, and (a(n)) and (b(n)) are increasing complementary sequences.at n=13A296245
• Number of ways to write n as an ordered sum of 7 nonprime numbers.at n=29A341484
• Integral area of primitive integer-sided triangles whose sides a < b < c are in arithmetic progression.at n=43A351178
• G.f. satisfies: A(x) = Series_Reversion(x - x^2*A'(x)^2).at n=5A360977