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 A166722 #22 Nov 28 2023 08:38:46 %S A166722 1,3,5,9,7,15,21,27,11,25,45,13,35,33,63,75,39,81,49,17,55,105,135,99, %T A166722 19,65,51,189,77,125,117,147,225,165,57,243,91,175,23,85,315,195,297, %U A166722 153,231,95,405,245,69,375,351,119,275,441,171,121,273,567,495,255,525 %N A166722 a(n) is the number of divisors of A166721(n). %C A166722 This is a permutation of the odd numbers A005408. - _Alois P. Heinz_, Mar 04 2018 %H A166722 Amiram Eldar, <a href="/A166722/b166722.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..300 from Alois P. Heinz) %F A166722 a(n) = A000005(A166721(n)). %e A166722 a(8) = A000005(A166721(8)) = A000005(900) = A000005(2^2 * 3^2 * 5^2) = (2+1)*(2+1)*(2+1) = 27. %Y A166722 Cf. A000005, A005408, A048691, A136404, A152674, A166721. %K A166722 easy,nonn %O A166722 1,2 %A A166722 Alexander Isaev (i2357(AT)mail.ru), Oct 20 2009 %E A166722 Proper definition (and removal of obscure Comments entries) by _Jon E. Schoenfield_, Mar 03 2018