A273664 a(n) = A249746(A032766(n)).

1, 3, 4, 5, 6, 7, 8, 10, 17, 11, 13, 26, 14, 15, 16, 18, 41, 20, 31, 21, 23, 40, 24, 25, 27, 48, 28, 30, 45, 33, 63, 54, 34, 35, 36, 37, 38, 43, 68, 70, 57, 115, 44, 46, 85, 47, 50, 74, 73, 51, 53, 87, 55, 107, 56, 58, 97, 60, 180, 61, 64, 96, 83, 65, 66, 67, 71, 114, 101, 100, 75, 110, 136, 108, 76, 77, 78, 80, 124, 81

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..10000

Formula

a(n) = A249746(A032766(n)).

a(n) = A249824(A254050(n)).

a(n) = A249746(A254049(A249745(n))).

Mathematica

t = PositionIndex[FactorInteger[#][[1, 1]] & /@ Range[10^6]]; f[n_] := Times @@ Power[If[# == 1, 1, NextPrime@ #] & /@ First@ #, Last@ #] &@ Transpose@ FactorInteger@ n; Flatten@ Map[Position[Lookup[t, FactorInteger[#][[1, 1]]], #] &[f@ f[2 #]] &, Map[Times @@ Power[If[# == 1, 1, NextPrime[#, -1]] & /@ First@#, Last@#] &@ Transpose@ FactorInteger[2 # - 1] &, Floor[#/2] + # & /@ Range@ 80]] (* Michael De Vlieger, Aug 07 2016, Version 10 *)

Prog

(Scheme) (define (A273664 n) (A249746 (A032766 n)))

Crossrefs

Cf. A032766, A249745, A249746, A249824, A254049, A254050, A275716.

Cf. also A273669 (natural numbers not in this sequence).

Sequence in context: A125684 A207669 A001272 * A364099 A332416 A047563

Adjacent sequences: A273661 A273662 A273663 * A273665 A273666 A273667

Keyword

nonn

Author

Antti Karttunen, Aug 06 2016

Status

approved