18870

Appears in sequences

• Positive numbers k such that k and 4*k are anagrams in base 9 (written in base 9).at n=29A023081
• Numbers k such that the sum of prime divisors of k is congruent to 2^k (mod k).at n=5A051423
• Number of ternary squarefree necklaces.at n=37A066297
• a(n) = least k such that the average number of divisors of {1..k} is >= n.at n=9A085829
• a(n) = floor(6^n/5^n).at n=54A094983
• The sum of a triangular array made from a negative 6 fold permutation product with shifts up and down of {2,6}.at n=40A105162
• Sequence is {a(3,n)}, where a(m,n) is defined at sequence A111518.at n=12A111521
• Number of (1+1) X (n+1) 0..3 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)+x(i-1,j) in the j direction.at n=10A250878
• Expansion of ( 1-2*x+3*x^2 ) / ( 1-4*x+5*x^2-4*x^3 ).at n=10A271897
• Areas of integer-sided triangles whose area equals 5 times their perimeter.at n=41A289221
• Column 5 of A060244.at n=24A291590
• Number of ways to write 2*n as an ordered sum of n squares of positive integers.at n=18A338464
• Perimeters of more than one primitive 120-degree integer triangle.at n=12A350047
• a(n) = the maximum number of distinct compositions of a polycube of size n using any combination of polycubes of sizes 1 through n.at n=10A367703