A076289 Numbers of the form (10^(m*r)-1)/(10^r-1) for positive integers m, r.

1, 11, 101, 111, 1001, 1111, 10001, 10101, 11111, 100001, 111111, 1000001, 1001001, 1010101, 1111111, 10000001, 11111111, 100000001, 100010001, 101010101, 111111111, 1000000001, 1001001001, 1111111111, 10000000001, 10000100001, 10101010101, 11111111111

Offset: 1

Author

N. J. A. Sloane, Nov 06 2002

Keywords

• nonn

Links

• Robert Israel, Table of n, a(n) for n = 1..7046
• T. Chinburg and M. Henriksen, Sums of k-th powers in the ring of polynomials with integer coefficients, Acta Arithmetica, 29 (1976), 227-250.

Crossrefs

Cf. A064896 (k=2), A076270 (k=3), A076275 (k=4), A076284 (k=5), A076285 (k=6), A076286 (k=7), A076287 (k=8), A076288 (k=9), A076289 (k=10).

Programs

Maple

N::= 20: # for terms <= 10^N
R:= {1}:
for n from 1 to 2*N do
  R:= R union select(`<=`, {seq((10^n-1)/(10^d-1), d = numtheory:-divisors(n))},10^N);
od:
sort(convert(R,list)); # Robert Israel, May 19 2024