1,1

Table of n, a(n) for n=1..16.

a(n) = A057494(n) - 2*10^n + 1 [From Max Alekseyev, May 10 2009]

a(1)=8 because there are 8 distinct divisors of composite numbers k through 10^1; these are for 4(1); 6(2); 8(2); 9(1); 10(2); and 1+2+2+1+2=8.

Cf. A136363.

Sequence in context: A226346 A217488 A247484 * A089670 A221612 A060355

Adjacent sequences: A136361 A136362 A136363 * A136365 A136366 A136367

easy,nonn

Enoch Haga, Dec 26 2007, Dec 29 2007

Edited by N. J. A. Sloane, Jan 12 2008

Three more terms from Max Alekseyev, May 10 2009

a(10) onward from Max Alekseyev, Jan 25 2010

approved