1,1

There are ~ Pi*n representations x^2 + y^2 of the numbers up to n, but only ~ K*n/sqrt(log n) of them are nonzero. Each of those nonzero numbers has on average (Pi/K)*sqrt(log n) such representations.

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Cf. A064533, A004018.

Sequence in context: A128760 A057884 A329637 * A016684 A324564 A276974

Adjacent sequences: A276831 A276832 A276833 * A276835 A276836 A276837

nonn,cons

Charles R Greathouse IV, Sep 19 2016

approved