18706

Appears in sequences

• Let r, s, t, u be four permutations of the set { 1, 2, 3, ..., n }; a(n) = minimal value of Sum_{i=1..n} r(i)*s(i)*t(i)*u(i).at n=13A070736
• 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=17A078420
• Expansion of 1/(1+x^2-x^3+x^4).at n=47A129903
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 0), (0, -1, 1), (1, 0, 1), (1, 1, -1), (1, 1, 1)}.at n=7A151002
• a(n) = a(n-1) + a(n-2) - [a(n-2)/4] - [a(n-4)/2] - [a(n-6)/4].at n=34A173599
• Number of partitions of n where the difference between consecutive parts is at most 2.at n=48A224956
• Those terms of A255571 whose every A080541/A080542-rotation is also a term of A255571.at n=31A258001
• Number of (n+1) X (1+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0001 0101 or 0111.at n=8A259290
• T(n,k)=Number of (n+1)X(k+1) 0..1 arrays with each 2X2 subblock having clockwise pattern 0001 0101 or 0111.at n=36A259297
• Number of (n+2)X(n+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00001001 or 00100101.at n=5A260972
• Number of (n+2)X(6+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00001001 or 00100101.at n=5A260978
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 110", based on the 5-celled von Neumann neighborhood.at n=39A270170
• Number of strings of length n composed of symbols from the circular list [1,2,3,4] such that adjacent symbols in the string must be adjacent in the list. No runs of length 2 or more are allowed for symbols 1 and 3.at n=10A277236
• Number of compositions of n with equal circular differences up to sign.at n=49A325558
• a(n) = Sum_{i=1..n, j=1..n, gcd(i,j)=1} i.at n=38A333297
• Centered pentagonal numbers which are products of three distinct primes.at n=12A364610