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 A208898 #9 Mar 03 2025 20:24:53
%S A208898 1,1,2,9,72,880,14946,331177,9157984,305879724,12036430600,
%T A208898 547226046939,28298540270928,1643380366183920,106042236588594096,
%U A208898 7535372761616117625,585204851983514095424,49344635724104556446660,4491848127809479571999928,439231681095730953672503448
%N A208898 A diagonal of rectangular table A208896: a(n) = A208896(n+2,n).
%C A208898 The g.f. of row n, R(n,x), in the rectangular table A208896 satisfies:
%C A208898 (1) R(n,x) = 1 + x*R(n,x)^n * [d/dx x/R(n,x)] for n>=0.
%C A208898 (2) [x^k] R(n,x)^(k-n+1) = [x^k] R(n,x)^(k-n) for k>=2.
%C A208898 Thus the main diagonal in A208896 obeys: A208896(n,n) = 0 for n>=2.
%F A208898 a(n) is divisible by n for n>=1.
%e A208898 a(n)/n = [1,1,3,18,176,2491,47311,1144748,33986636,1203643060,...] for n>=1.
%o A208898 (PARI) {a(n)=local(ROW=1+x+x*O(x^n));for(i=0,n,ROW=1+x*ROW^(n+2)*deriv(x/ROW));polcoeff(ROW,n)}
%o A208898 for(n=0,20,print1(a(n),", "))
%Y A208898 Cf. A208896, A208897.
%K A208898 nonn
%O A208898 0,3
%A A208898 _Paul D. Hanna_, Mar 03 2012