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6, 9, 15, 21, 33, 39, 51, 57, 69, 87, 93, 111, 123, 129, 141, 159, 177, 183, 201, 213, 219, 237, 249, 267, 291, 303, 309, 321, 327, 339, 381, 393, 411, 417, 447, 453, 471, 489, 501, 519, 537, 543, 573, 579, 591, 597, 633, 669, 681, 687, 699, 717, 723, 753
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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COMMENTS
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A164023(a(n)) = A164024(a(n)) = A000040(n). [From Reinhard Zumkeller, Aug 09 2009]
Semiprimes of the form m*k such that m/(k-2)=prime. [From Juri-Stepan Gerasimov, May 25 2010]
The sum of two distinct terms from sequence A179545. [From Odimar Fabeny, Aug 18 2010]
Solutions of the differential equation n'=1/3*(n+9), where n' is the arithmetic derivative of n. - Paolo P. Lava, Feb 02 2012.
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LINKS
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Paolo P. Lava, Table of n, a(n) for n = 1..20000
Eric Weisstein's World of Mathematics, Skeleton
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FORMULA
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a(n) = 3*A000040(n). - Omar E. Pol, Jan 31 2012
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MATHEMATICA
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Prime[Range[22]]*3 (* Vladimir Joseph Stephan Orlovsky, Apr 29 2008 *)
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PROG
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(PARI) 3*primes(22) \\ Charles R Greathouse IV, May 19, 2011
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CROSSREFS
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Subsequence of A001358.
Cf. A179545 [From Odimar Fabeny, Aug 18 2010]
Sequence in context: A203468 A164383 A168544 * A097426 A075278 A102971
Adjacent sequences: A001745 A001746 A001747 * A001749 A001750 A001751
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KEYWORD
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nonn,easy,changed
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AUTHOR
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N. J. A. Sloane.
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STATUS
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approved
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