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 A165499 #15 Nov 29 2016 21:23:32 %S A165499 1,3,4,5989,16 %N A165499 First term of maximal arithmetic progression with difference n, such that each term k has tau(k) = n. %C A165499 a(6) <= 161804009483982959337354063701 if A165498(6) = 9, and at least 1e14. %C A165499 a(8) = 380017309607. %C A165499 a(10) <= 43920665884407841463671 if A165498(10) = 5 (found by _Giovanni Resta_), and at least 1e12. %C A165499 a(12) <= 11673662470957217427690002629075 if A165498(12) = 10, and at least 1e10. %C A165499 a(16) = 2a(8). %C A165499 A165498(n) = 1 for odd n, so a(7) = 64; a(9) = 36; a(11) = 1024; a(13) = 4096; a(15) = 144; etc. %e A165499 A165498(4) = 8, and exhaustive search finds tau(5989) = tau(5993) = tau(5997) = tau(6001) = tau(6005) = tau(6009) = tau(6013) = tau(6017) = 4 is the first example of an 8-term progression, so a(4) = 5989. %Y A165499 Cf. A064491, A165497, A165498, A165501. %K A165499 hard,nonn,more %O A165499 1,2 %A A165499 _Hugo van der Sanden_, Sep 21 2009; updated Nov 29 2016