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 A212640 #12 Oct 27 2024 03:25:46 %S A212640 1,3,4,5,6,9,7,12,8,15,16,9,18,20,10,21,24,27,11,24,25,28,36,12,27,30, %T A212640 32,45,13,30,35,48,36,54,36,14,33,40,60,40,63,42,15,36,45,72,64,44,72, %U A212640 48,75,16,39,50,84,81,49,80,48,81,54,90,17,42,55,96,108 %N A212640 Number of divisors of A181800(n) (n-th powerful number that is the first integer of its prime signature). %H A212640 Amiram Eldar, <a href="/A212640/b212640.txt">Table of n, a(n) for n = 1..10000</a> %F A212640 a(n) = A000005(A181800(n)). %e A212640 A181800(6) = 36 has 9 divisors (1, 2, 3, 4, 6, 9, 12, 18 and 36). Hence, a(6) = 9. %Y A212640 Cf. A181800, A000005, A212641. %K A212640 nonn %O A212640 1,2 %A A212640 _Matthew Vandermast_, Jun 09 2012