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 A078264 #11 Jan 20 2025 22:49:26 %S A078264 1,15,198,2309,25895,284217,3074048,32896079,349188532,11646890238, %T A078264 1171148874112,122278263238675,12727490844526758,1320830780128673820, %U A078264 136722265049041488664,14120912163801368446154,1455577353063960520275521,149780147487160167412789089 %N A078264 Integer part of the geometric mean of the forward and reverse concatenations of 1 to n. %F A078264 a(n) = floor(A078263(n)^(1/2)). %e A078264 a(3) = floor(sqrt(123*321)) = floor(sqrt(39483)) = 198. %o A078264 (PARI) f="1";b="1";for(i=2,40,print1(sqrtint(eval(f)*eval(b)),",");f=concat(f,Str(i));b=concat(Str(i),b)) \\ Lambert Herrgesell (zero815(AT)googlemail.com), Mar 13 2006 %Y A078264 Cf. A078263. %K A078264 base,nonn %O A078264 1,2 %A A078264 _Amarnath Murthy_, Nov 24 2002 %E A078264 More terms from Lambert Herrgesell (zero815(AT)googlemail.com), Mar 13 2006