180731

Properties

Appears in sequences

• Primes for which only three iterations of 'Prime plus its digit sum equals a prime' are possible.at n=31A048525
• Trajectory of 23 under map that sends x to 3x - sigma(x), where sigma(x) is the sum of the divisors of x.at n=16A058545
• Dimension of 4-variable non-commutative harmonics (Hausdorff derivative). The dimension of the space of non-commutative polynomials in 4 variables which are killed by all symmetric differential operators (where for a monomial w, d_{xi} ( w ) = sum over all subwords of w deleting xi once).at n=9A122393
• Prime numbersat n=16399