|
%I #15 Sep 24 2018 08:54:58
%S 1,3,7,9,13,21,19,27,49,39,29,63,37,57,91,81,43,147,53,117,133,87,61,
%T 189,169,111,343,171,71,273,79,243,203,129,247,441,89,159,259,351,101,
%U 399,107,261,637,183,113,567,361,507,301,333,131,1029,377,513,371
%N Completely multiplicative with a(prime(k)) = prime(2 * k) (where prime(k) denotes the k-th prime).
%C This sequence is a permutation of {1} union A066207.
%C This sequence is the third row of A248601.
%H Rémy Sigrist, <a href="/A297002/b297002.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A248601(3, n) for any n > 0.
%t Array[Times @@ Map[Power @@ # &, FactorInteger[#] /. {p_, e_} /; p > 1 :> {Prime[2 PrimePi@ p], e}] &, 57] (* _Michael De Vlieger_, Dec 23 2017 *)
%o (PARI) a(n) = my (f=factor(n)); prod(i=1, #f~, prime(2 * primepi(f[i,1]))^f[i,2])
%Y Cf. A066207, A248601.
%K easy,nonn,mult
%O 1,2
%A _Rémy Sigrist_, Dec 23 2017
%E Comment corrected by _Rémy Sigrist_, Sep 22 2018
|
