161257

Appears in sequences

• Numbers k such that sigma(k)*phi(k) is a palindrome.at n=14A115892
• Number of nX2 0..3 arrays with every row and column running average nondecreasing rightwards and downwards.at n=7A201210
• T(n,k)=Number of nXk 0..3 arrays with every row and column running average nondecreasing rightwards and downwards.at n=37A201216
• Odd numbers k, not powers of primes, such that sigma(k) == 2 modulo 8 and sigma(sigma(k)) == 6 modulo 8.at n=25A332458
• Odd composites k, not powers of primes, such that for all their nontrivial unitary divisors d it holds that A347381(d) > A347381(k).at n=7A347383
• Positions of 3's in A347381.at n=27A347393
• After the initial 1, numbers k such that A347381 obtains its minimum value at k, of all the divisors d of k larger than one, where A347381 is the distance from n to the nearest common ancestor of n and sigma(n) in the Doudna-tree (A005940).at n=41A374218
• Odd numbers k such that k/(1+A347381(k)) obtains record values, where A347381 gives the distance from n to the nearest common ancestor of n and sigma(n) in the Doudna-tree.at n=34A386423