221000

Appears in sequences

• Numbers m such that DivisorSigma(4*k-2, m) mod m = 0 holds presumably for all k; that is, (4k-2)-power-sums of divisors of m are divisible by m for all k.at n=24A066290
• The common value of sigma_2 for square-amicable numbers, sigma_2(m)=sigma_2(n), m<n.at n=32A110929
• Number of permutations of floor(i*4/3), i=0..n-1, with all sums of 4 adjacent terms unique.at n=8A152334
• For every positive integer m, let u(m) = (d(1),d(2),...,d(k)) be the unitary divisors of m. The sequence (a(n)) consists of successive numbers m which d(k)/d(1) + d(k-1)/d(2) + ... + d(k)/d(1) is an integer.at n=26A229996
• Number of (n+2) X (7+2) 0..1 arrays with no 3 X 3 subblock diagonal sum less than the antidiagonal sum or central row sum less than the central column sum.at n=16A258893
• The smallest number k that can be partitioned in n ways as the sum of two numbers from A020487.at n=29A369384
• Ternary numbers consisting of a run of 2's, then a run of 1's, then a run of 0's.at n=14A371053
• Ternary numbers that are concatenated runs C(1)A(1)B(1)C(2)A(2)B(2)...C(k)A(k)B(k), where A(i) is a run of 1's, B(i) a run of 0's, and C(i) a run of 2's, for i = 1..k.at n=15A371111