A076287 Numbers of the form (8^{mr}-1)/(8^r-1) for positive integers m, r.

1, 9, 65, 73, 513, 585, 4097, 4161, 4681, 32769, 37449, 262145, 262657, 266305, 299593, 2097153, 2396745, 16777217, 16781313, 17043521, 19173961, 134217729, 134480385, 153391689, 1073741825, 1073774593, 1090785345, 1227133513, 8589934593, 9817068105

Offset

1,2

Comments

Numbers which in base 8 contain only 0's and 1's, with equally spaced 1's. - Robert Israel, Jan 15 2019

Links

Robert Israel, Table of n, a(n) for n = 1..7932

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((8^(k+r)-1)/(8^r-1), r = ListTools:-Reverse(sort(convert(numtheory:-divisors(k), list)))), k=1..20); # Robert Israel, Jan 15 2019

Crossrefs

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

Sequence in context: A043426 A038484 A043021 * A339997 A226929 A212668

Adjacent sequences: A076284 A076285 A076286 * A076288 A076289 A076290

Keyword

nonn

Author

N. J. A. Sloane, Nov 06 2002

Status

approved