22024

Appears in sequences

• Numbers n such that h(n) = 3 h(n-1) where h(n) is the length of the sequence {n, f(n), f(f(n)), ...., 1} in the Collatz (or 3x + 1) problem. (The earliest "1" is meant.)at n=20A078420
• Number of integer partitions of n with a part dividing all the other parts.at n=38A083710
• G.f.: ( x - 3*x^2 + 6*x^3 - 8*x^4 + 4*x^5 - x^7 ) / (1 - 4*x + 6*x^2 - 5*x^3 + 2*x^4 + x^5 - x^6 + x^7 ).at n=18A083839
• Number of n X 3 0..2 arrays with no element x(i,j) adjacent to value 2-x(i,j) horizontally, vertically or antidiagonally.at n=7A232936
• T(n,k)=Number of nXk 0..2 arrays with no element x(i,j) adjacent to value 2-x(i,j) horizontally, vertically or antidiagonally.at n=47A232941
• Number of integer compositions of n that have only one part or whose consecutive parts are indivisible and the last and first part are also indivisible.at n=29A318726
• Array read by antidiagonals: T(n,k) is the number of nonisomorphic multisets of permutations of an n-set with k permutations.at n=63A362644
• Number of nonisomorphic unordered pairs of permutations of an n-set.at n=8A362645
• a(n) is the number of distinct solution sets to the quadratic equations u*x^2 + v*x + w = 0 with integer coefficients u, v, w, abs(u) + abs(v) + abs(w) <= n having a nonnegative discriminant.at n=38A379597