This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A076284 #6 Jun 12 2015 20:05:53
%S A076284 1,6,26,31,126,156,626,651,781,3126,3906,15626,15751,16276,19531,
%T A076284 78126,97656,390626,391251,406901,488281,1953126,1968876,2441406,
%U A076284 9765626,9768751,10172526,12207031,48828126,61035156,244140626,244156251,244531876,246109501
%N A076284 Numbers of the form (5^{mr}-1)/(5^r-1) for positive integers m, r.
%H A076284 T. Chinburg and M. Henriksen, <a href="http://matwbn.icm.edu.pl/ksiazki/aa/aa29/aa2932.pdf">Sums of k-th powers in the ring of polynomials with integer coefficients</a>, Acta Arithmetica, 29 (1976), 227-250.
%Y A076284 Cf. A064896 (k=2), A076270 (k=3), A076275 (k=4), A076285 (k=6), A076286 (k=7), A076287 (k=8), A076288 (k=9), A076289 (k=10).
%K A076284 nonn
%O A076284 1,2
%A A076284 _N. J. A. Sloane_, Nov 06 2002