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 A173252 #15 Oct 05 2019 04:43:14
%S A173252 2,1,2,19,2,289,118,41,182578,239803,495074,3866257,1158454,2629057,
%T A173252 56207062,82084427,4638842098,5389722857,30867186934,8585039713,
%U A173252 5319558074,2,193589999521,616960854422,5663407855939,5264528838038
%N A173252 A sequence of coefficients of 3^n when x_n = x_oi.
%C A173252 The paper is not yet published - it can be furnished on request.
%C A173252 Sequence of x_n: 0, 3, 12, 39, 66, 795, 1524, 8085, 539526, 1070967, 2665290, ...
%C A173252 The x_n are given by recurrence x_(n+1) = x_n + 3^(s_n - 1), where s_n is the exponent of the highest power of 3 in v_n = x_n^2 + 18, and the a(n) are equal to v_n / 3^s_n.
%D A173252 A. K. Devaraj, A theorem a la Ramanujan, Joint Meeting of AMS-BENELUX, '96.
%o A173252 (PARI) lista(nn) = {x = 0; for (i=1, nn, y = x^2 + 18; s = valuation(y, 3); f = z^2 + 18; fx = subst(f, z, x); p3 = valuation (fx, 3); print1(fx/3^p3, ", "); x += 3^(s-1););} \\ _Michel Marcus_, Aug 08 2013
%K A173252 nonn,uned,obsc
%O A173252 1,1
%A A173252 _A.K. Devaraj_, Feb 14 2010
%E A173252 More terms from _Michel Marcus_, Aug 08 2013