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A076270

Numbers of the form (3^{mr}-1)/(3^r-1) for positive integers m, r.

1, 4, 10, 13, 28, 40, 82, 91, 121, 244, 364, 730, 757, 820, 1093, 2188, 3280, 6562, 6643, 7381, 9841, 19684, 20440, 29524, 59050, 59293, 66430, 88573, 177148, 265720, 531442, 532171, 538084, 551881, 597871, 797161, 1594324, 2391484, 4782970, 4785157, 5380840

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..41.

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

f := proc(p) local m, r, t1; t1 := {}; for m from 1 to 10 do for r from 1 to 10 do t1 := {op(t1), (p^(m*r)-1)/(p^r-1)}; od: od: sort(convert(t1, list)); end; f(3); # very crude!

CROSSREFS

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

Sequence in context: A191107 A173931 A173793 * A032821 A101576 A179134

Adjacent sequences: A076267 A076268 A076269 * A076271 A076272 A076273

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Nov 06 2002

STATUS

approved