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 A001226 #21 Dec 19 2017 02:23:04
%S A001226 1,1,3,9,7,93,315,17,3855,13797,195,182361,41943,9709,9256395,
%T A001226 34636833,31775,479349,1857283155,430185,26817356775,102280151421,
%U A001226 372827,1497207322929,89756051247,84215045,84973577874915,19991120505,1205604855,4885260612740877
%N A001226 Lerch's function q_2(n) = (2^{phi(t)} - 1)/t where t = 2*n - 1.
%C A001226 Lerch defines q_u = (u^phi(p) - 1)/p for any odd integer p and for u prime to p. - _Altug Alkan_, Dec 19 2017
%D A001226 L. E. Dickson, History of the Theory of Numbers. Carnegie Institute Public. 256, Washington, DC, Vol. 1, 1919; Vol. 2, 1920; Vol. 3, 1923, see vol. 1, p. 109.
%H A001226 T. D. Noe, <a href="/A001226/b001226.txt">Table of n, a(n) for n = 1..200</a>
%H A001226 R. C. Read, <a href="/A000684/a000684_1.pdf">Letter to N. J. A. Sloane, Oct. 29, 1976</a>
%t A001226 Table[(2^EulerPhi[n] - 1)/n, {n, 1, 40, 2}] (* _T. D. Noe_, Jun 26 2012 *)
%o A001226 (PARI) a(n) = (2^eulerphi(2*n-1) - 1)/(2*n-1) \\ _Andrew Howroyd_, Dec 18 2017
%Y A001226 Cf. A000010.
%K A001226 nonn
%O A001226 1,3
%A A001226 _N. J. A. Sloane_