A076286 Numbers of the form (7^{mr}-1)/(7^r-1) for positive integers m, r.

1, 8, 50, 57, 344, 400, 2402, 2451, 2801, 16808, 19608, 117650, 117993, 120100, 137257, 823544, 960800, 5764802, 5767203, 5884901, 6725601, 40353608, 40471600, 47079208, 282475250, 282492057, 288360150, 329554457, 1977326744, 2306881200, 13841287202

Offset

1,2

Links

Robert Israel, Table of n, a(n) for n = 1..8539

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

[1, seq(seq((7^(d+r)-1)/(7^r-1), r = sort(convert(numtheory:-divisors(d), list), `>`)), d=1..20)]; # Robert Israel, Aug 27 2018

Crossrefs

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

Sequence in context: A043398 A038481 A043015 * A299049 A299811 A280600

Adjacent sequences: A076283 A076284 A076285 * A076287 A076288 A076289

Keyword

nonn

Author

N. J. A. Sloane, Nov 06 2002

Status

approved