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 A385206 #13 Jun 21 2025 11:49:23
%S A385206 1,7,-98,1715,-28812,369754,0,-234003861,11187831655,-379208609780,
%T A385206 10505577339166,-237021026782414,3747904201751920,0,
%U A385206 -3136632447485449416,165539296779239527515,-6087083256734433868530,180571542422445599417377,-4318405727843353425012650
%N A385206 G.f. A(x) satisfies A(x) = ( 1 + 49*x*A(x) )^(1/7).
%H A385206 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A385206 a(n) = 49^n * binomial(n/7+1/7,n)/(n+1).
%F A385206 G.f. A(x) satisfies A(x) = 1/A(-x/A(x)^5).
%F A385206 G.f.: (1/x) * Series_Reversion(x/(1+49*x)^(1/7)).
%F A385206 a(7*n+6) = 0 for n >= 0.
%o A385206 (PARI) a(n) = 49^n*binomial(n/7+1/7, n)/(n+1);
%o A385206 (PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x/(1+49*x)^(1/7))/x)
%Y A385206 Cf. A385207, A385208.
%Y A385206 Cf. A182122.
%K A385206 sign
%O A385206 0,2
%A A385206 _Seiichi Manyama_, Jun 21 2025