

A066066


a(n) = prime(2*n)  2*prime(n).


16



1, 1, 3, 5, 7, 11, 9, 15, 15, 13, 17, 15, 19, 21, 19, 25, 21, 29, 29, 31, 35, 35, 33, 45, 35, 37, 45, 49, 53, 55, 39, 49, 43, 59, 51, 57, 59, 57, 63, 63, 63, 71, 61, 71, 69, 81, 69, 57, 67, 83, 91, 91, 95, 91, 87, 87, 81, 99, 93, 97, 107, 97, 87, 97, 107, 109, 95, 95, 93, 111, 115, 109, 105, 111, 105, 115, 109, 117, 127, 123, 115
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OFFSET

1,3


COMMENTS

a(n) = A022457(n) for n > 1.
a(n) = A031215(n)A100484(n) = A072473(n)A000040(n); see A179740 for primes.  Reinhard Zumkeller, Jul 25 2010
Asymptotically, a(n) ~ log(4) n, with log(4) = 2 log 2 = 1.38629436111989... = A016627.  M. F. Hasler, Oct 19 2013


LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000


MATHEMATICA

Table[Prime[2n]2Prime[n], {n, 100}] (* Harvey P. Dale, Aug 21 2016 *)


PROG

(PARI) { for (n = 1, 1000, a=prime(2*n)  prime(n)*2; write("b066066.txt", n, " ", a) ) } \\ Harry J. Smith, Nov 09 2009
(PARI) A066066(n)=prime(2*n)2*prime(n) \\ M. F. Hasler, Oct 19 2013


CROSSREFS

Sequence in context: A245462 A338842 A022457 * A241957 A112070 A208643
Adjacent sequences: A066063 A066064 A066065 * A066067 A066068 A066069


KEYWORD

sign


AUTHOR

Reinhard Zumkeller, Dec 01 2001


STATUS

approved



