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

1,2

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.

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

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).

Sequence in context: A333415 A264406 A057148 * A350346 A247647 A240602

Adjacent sequences: A076286 A076287 A076288 * A076290 A076291 A076292

Keyword

nonn

Author

N. J. A. Sloane, Nov 06 2002

Status

approved