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 A027747 #14 Jul 08 2025 17:54:57 %S A027747 1,65536,7625597484987,256,5 %N A027747 a(n) = n^n^n^..^n (6-n terms, n<=5). %C A027747 The creator of the test asked me to remove this sequence. But one of the reasons for creating this database was to help people do these tests. This was stated already in the 1973 Handbook of Integer Sequences. Many sequences in the database have appeared on IQ tests. %H A027747 P. Cooijmans, <a href="http://www.eskimo.com/~miyaguch/tfg/tfg.html">Test for Genius (Short Form)</a> [broken link] %H A027747 Paul Cooijmans, <a href="http://web.archive.org/web/20050302171708/http://members.chello.nl/p.cooijmans/gliaweb/tests/num.html">Numbers</a>. %H A027747 Paul Cooijmans, <a href="http://web.archive.org/web/20031006141136/http://members.chello.nl/p.cooijmans/gliaweb/tests/tfg/tfgshort.html">Short Test For Genius</a>. %e A027747 a(1) = 1^(1^(1^(1^1))) = 1. %e A027747 a(2) = 2^(2^(2^2)) = 2^16. %e A027747 a(3) = 3^(3^3) = 3^27. %e A027747 a(4) = 4^4. %e A027747 a(5) = 5. %p A027747 b:= (n, i)-> `if`(i=0, 1, n^b(n, i-1)): %p A027747 a:= n-> b(n, 6-n): %p A027747 seq(a(n), n=1..5); # _Alois P. Heinz_, Aug 22 2017 %Y A027747 Cf. A004231, A049384, A051441. %K A027747 nonn,fini,full %O A027747 1,2 %A A027747 Sent in by an anonymous correspondent %E A027747 Examples from _Martin Renner_, Aug 22 2017