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

Offset: 1

Author

N. J. A. Sloane, Nov 06 2002

Keywords

• nonn

Links

• 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), A076286 (k=7), A076287 (k=8), A076288 (k=9), A076289 (k=10).

Programs

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!