The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A243505 Permutation of natural numbers, take the odd bisection of A122111 and divide the largest prime factor out: a(n) = A052126(A122111(2n-1)). 17
 1, 2, 4, 8, 3, 16, 32, 6, 64, 128, 12, 256, 9, 5, 512, 1024, 24, 18, 2048, 48, 4096, 8192, 10, 16384, 27, 96, 32768, 36, 192, 65536, 131072, 20, 72, 262144, 384, 524288, 1048576, 15, 54, 2097152, 7, 4194304, 144, 768, 8388608, 108, 1536, 288, 16777216, 40, 33554432, 67108864, 30 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Antti Karttunen, Table of n, a(n) for n = 1..1024 Indranil Ghosh, Python program for computing the sequence FORMULA a(n) = A052126(A122111((2*n)-1)). a(n) = A122111((2*n)-1) / A105560((2*n)-1). As a composition of related permutations: a(n) = A122111(A064216(n)). a(n) = A241916(A243065(n)). Other identities: For all n >= 2, a(n) = A070003(A244984(n)-1) / A105560((2*n)-1). For all n >= 1, a(A006254(n)) = A000079(n) and a(A007051(n)) = A000040(n). For all n >= 1, A105560(2n-1) divides a(n). MATHEMATICA A052126[n_] := n/FactorInteger[n][[-1, 1]]; A122111[n_] := Product[Prime[Sum[If[j < i, 0, 1], {j, #}]], {i, Max[#]}]&[ Flatten[Table[Table[PrimePi[f[[1]]], {f[[2]]}], {f, FactorInteger[n]}]]]; a[n_] := A052126[A122111[2n-1]]; Array[a, 60] (* Jean-François Alcover, Sep 23 2020 *) PROG (Scheme) (define (A243505 n) (A122111 (A064216 n))) CROSSREFS Inverse: A243506. Cf. A000040, A000079, A006254, A007051, A052126, A105560. Related or similar permutations: A122111, A064216, A241916, A243065-A243066, A244981-A244982, A244983-A244984, A244153-A244154. Sequence in context: A119436 A277695 A317503 * A243065 A289271 A341811 Adjacent sequences:  A243502 A243503 A243504 * A243506 A243507 A243508 KEYWORD nonn AUTHOR Antti Karttunen, Jun 25 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 September 17 16:00 EDT 2021. Contains 347478 sequences. (Running on oeis4.)