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 A185097 #28 Apr 25 2023 06:17:13 %S A185097 1,36,41616,55420693056,98286503002057414584576, %T A185097 309127573515950117423442905473334441338685531136 %N A185097 a(1)=1; thereafter a(n+1) = T(8*a(n)), where T(i)=i*(i+1)/2 is the i-th triangular number. %C A185097 All terms are square and triangular; a subsequence of A001110. %D A185097 C. Alsina and R. B. Nelson, Charming Proofs: A Journey into Elegant Mathematics, MAA, 2010. See p. 4. %F A185097 a(n) = (1/8)*sinh(2^(n-2)*arccosh(17))^2. [_Alexander R. Povolotsky_, Aug 14 2011] %F A185097 a(n+2) = 4*a(n+1)*(a(n+1)/(2*a(n))-1)^2, a(1)=1, a(2)=36. [_Alexander R. Povolotsky_, Aug 15 2011] %F A185097 a(n) = A001110(2^(n-1)). - _Ivan N. Ianakiev_, Mar 11 2014 %p A185097 T:=n->n*(n+1)/2; t1:=[1]; for n from 1 to 7 do t1:= [op(t1), T(8*t1[nops(t1)])]; od: t1; %t A185097 NestList[(8#(8#+1))/2&,1,7] (* _Harvey P. Dale_, Jan 20 2015 *) %Y A185097 Cf. A000217, A001110, A185096. %K A185097 nonn %O A185097 1,2 %A A185097 _N. J. A. Sloane_, Feb 18 2011