1,9

Table of n, a(n) for n=1..105.

(PARI) for(n=1, 130, print1(sum(i=1, n, sum(j=1, n, if(numdiv(i^j)-i-j, 0, 1))), ", "))

Cf. A000005.

Sequence in context: A067100 A296237 A074802 * A280953 A111894 A279012

Adjacent sequences: A071801 A071802 A071803 * A071805 A071806 A071807

nonn

Benoit Cloitre, Jun 06 2002

approved