55680

Appears in sequences

• Riordan array (1/(1-2x), x(1-x)/(1-2x)^2).at n=57A114164
• Triangular sequence of coefficients from a polynomial recursion: p(x,n)=-2 (-(n - 1) + x)*p(x, n - 1) + (-(n + 1) + (n + 2)* x - x^2)p(x, n - 2).at n=49A137663
• Numbers with prime factorization pqrs^7.at n=12A190473
• Expansion of e.g.f. 1/(1+Pi/4-arctan(2*x+1)).at n=9A199043
• Twice A137829.at n=19A201078
• Number of solutions to x^2 + y^2 + z^2 + t^2 == n (mod 2*n) for x,y,z,t in [0, 2*n).at n=19A229294
• a(n) = 2^n mod n^3.at n=40A233442
• Number of (n+1) X (3+1) 0..2 arrays colored with the upper median value of each 2 X 2 subblock.at n=13A235949
• Number of nX3 0..3 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of elements above it or three plus the sum of the elements diagonally to its northwest, modulo 4.at n=4A240343
• Number of nX5 0..3 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of elements above it or three plus the sum of the elements diagonally to its northwest, modulo 4.at n=2A240345
• T(n,k)=Number of nXk 0..3 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of the elements above it or three plus the sum of the elements diagonally to its northwest, modulo 4.at n=23A240347
• T(n,k)=Number of nXk 0..3 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of the elements above it or three plus the sum of the elements diagonally to its northwest, modulo 4.at n=25A240347
• Check the abundance of a number and iterate the test replacing at every step the sum of the divisors of the previous number. Sequence lists the least numbers whose abundances last n steps.at n=13A286659
• Numbers k such that k = Product (p_j^e_j) = Product (p_j*(e_j + 1)).at n=16A304410
• Numbers k for which A306927(k) [= A001615(k)-k] is a multiple of A344705(k) [= A001615(k)-A001065(k)], and their quotient is nonnegative.at n=50A344700
• Triangle read by rows: T(n,k) is the number of permutations of length n that have k same elements at the same positions with its inverse permutation for 0 <= k <= n.at n=62A344901