This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A243283 One more than the partial sums of the characteristic function of A070003. 5
 1, 1, 1, 2, 2, 2, 2, 3, 4, 4, 4, 4, 4, 4, 4, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 15, 15, 15, 16 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS a(n) tells how many natural numbers <= n there are which are divisible by the square of their largest noncomposite divisor. (This definition includes 1 as it is divisible by 1^2). a(n) = n - A243285(n). a(1)=1 and for all n>1, a(A070003(n-1)) = n, thus this sequence works as an inverse function for the injection {a(1)=1, a(n>1)=A070003(n-1)} (a sequence which is an union of {1} and A070003). LINKS Antti Karttunen, Table of n, a(n) for n = 1..10000 PROG (Scheme, with memoizing macro definec from Antti Karttunen's IntSeq-library) (definec (A243283 n) (if (<= n 1) n (+ (A243283 (- n 1)) (if (zero? (A241917 n)) 1 0)))) CROSSREFS One more than A243282. Differs from A243284 for the first time at n=48. Here a(48)=10. Cf. A070003, A102354, A243285, A057627. Sequence in context: A069623 A076411 A217038 * A243284 A072613 A029551 Adjacent sequences:  A243280 A243281 A243282 * A243284 A243285 A243286 KEYWORD nonn AUTHOR Antti Karttunen, Jun 02 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 26 07:44 EDT 2019. Contains 323579 sequences. (Running on oeis4.)