18370

Appears in sequences

• a(n) = n*(19*n - 1)/2.at n=44A022276
• 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=13A078420
• Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 11011-01110 pattern in any orientation.at n=15A147229
• Coefficient of x in the reduction by x^2 -> x+1 of the polynomial p(n,x) defined at Comments.at n=16A192955
• The 240-degree spoke (or ray) of a hexagonal spiral of Ulam.at n=39A244805
• Number of pairs (lambda,mu) of partitions lambda of n and mu of four with mu <= lambda (by diagram containment).at n=24A303854
• Number of compositions of n into parts 1, 8, 9.at n=42A322405
• G.f. satisfies A(x) = x + Product_{n>=2} A(x^n) with A(0) = 1.at n=41A385635