221088

Appears in sequences

• a(n) = floor( n*(n-1)*(n-2)*(n-3)/23 ).at n=49A011933
• Composite numbers k such that phi(k) divides sigma(k) - 2*k.at n=31A068412
• Numbers k such that (sigma(k) + sigma(k + sigma(k))) / k is an integer where sigma(k) = A000203(k) is the sum of the divisors of k.at n=29A383392
• Square array A(n,k) = A388979(A388981(n, k)), read by descending antidiagonals.at n=38A389169
• Numbers k such that sigma(k) = 2*k + 4*phi(k).at n=3A392692