This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A290104 a(n) = A003963(n) / A290103(n). 7
 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 1, 3, 1, 4, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 1, 4, 3, 1, 1, 1, 4, 1, 1, 2, 1, 1, 1, 1, 1, 4, 1, 3, 1, 1, 1, 1, 1, 1, 2, 1, 1, 3, 1, 1, 2, 1, 1, 8, 1, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 4, 2, 3, 1, 1, 1, 1, 2, 1, 1, 4, 1, 1, 2, 1, 1, 2, 3, 1, 4, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,9 COMMENTS The Heinz number of an integer partition (y_1, ..., y_k) is prime(y_1) * ... * prime(y_k). Then a(n) is the product divided by the LCM of the integer partition with Heinz number n. - Gus Wiseman, Aug 01 2018 LINKS Antti Karttunen, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A003963(n) / A290103(n). Other identities. For all n >= 1: a(A181819(n)) = A005361(n)/A072411(n). EXAMPLE n = 21 = 3 * 7 = prime(2) * prime(4), thus A003963(21) = 2*4 = 8, while A290103(21) = lcm(2,4) = 4, so a(21) = 8/4 = 2. MATHEMATICA Table[If[n == 1, 1, Apply[Times, Map[PrimePi[#1]^#2 & @@ # &, #]] / Apply[LCM, PrimePi[#[[All, 1]] ]]] &@ FactorInteger@ n, {n, 120}] (* Michael De Vlieger, Aug 14 2017 *) PROG (Scheme) (define (A290104 n) (/ (A003963 n) (A290103 n))) CROSSREFS Differs from A290106 for the first time at n=21. Cf. A003963, A056239, A074761, A289509, A290103, A290105, A296150, A316429, A316431. Sequence in context: A290106 A060128 A327407 * A308479 A031280 A134870 Adjacent sequences:  A290101 A290102 A290103 * A290105 A290106 A290107 KEYWORD nonn AUTHOR Antti Karttunen, Aug 13 2017 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 October 15 07:56 EDT 2019. Contains 328026 sequences. (Running on oeis4.)