1,1

See also comments in A053474.

Table of n, a(n) for n=1..63.

a(n) = A000203(A007369(n)).

The 13th non-sigma number is 26. Its divisors are {26,13,2,1} of which the sum is 42. So a(13)=42. Also a(20)=42, the divisor sum of 20th term in A007369, which is 41.

Cf. A000203, A007369, A053474.

Sequence in context: A189420 A215972 A145604 * A310123 A293794 A115283

Adjacent sequences: A053566 A053567 A053568 * A053570 A053571 A053572

nonn

Labos Elemer, Jan 17 2000

approved