

A002373


Smallest prime in decomposition of 2n into sum of two odd primes.
(Formerly M2273 N0899)


25



3, 3, 3, 5, 3, 3, 5, 3, 3, 5, 3, 5, 7, 3, 3, 5, 7, 3, 5, 3, 3, 5, 3, 5, 7, 3, 5, 7, 3, 3, 5, 7, 3, 5, 3, 3, 5, 7, 3, 5, 3, 5, 7, 3, 5, 7, 19, 3, 5, 3, 3, 5, 3, 3, 5, 3, 5, 7, 13, 11, 13, 19, 3, 5, 3, 5, 7, 3, 3, 5, 7, 11, 11, 3, 3, 5, 7, 3, 5, 7, 3, 5, 3, 5, 7, 3, 5, 7, 3, 3, 5, 7, 11, 11, 3, 3, 5, 3
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OFFSET

3,1


COMMENTS

See A020481 for another version.
a(A208662(n)) = A065091(n) and a(m) <> A065091(n) for m < A208662(n).  Reinhard Zumkeller, Feb 29 2012
Records are in A025019, their indices in A051610.  Ralf Stephan, Dec 29 2013


REFERENCES

D. H. Lehmer, Guide to Tables in the Theory of Numbers. Bulletin No. 105, National Research Council, Washington, DC, 1941, p. 80.
N. Pipping, Neue Tafeln fuer das Goldbarsche Gesetz nebst Berichtungen zu den Haussnerschen Tafeln, Finska VetenskapsSocieteten, Comment. Physico Math.. 4 (No. 4, 1927), 27 pp.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

T. D. Noe, Table of n, a(n) for n = 3..10000
Eric Weisstein's World of Mathematics, Goldbach Partition
Wikipedia, Goldbach's conjecture
Index entries for sequences related to Goldbach conjecture


MATHEMATICA

Table[k = 2; While[q = Prime[k]; ! PrimeQ[2*n  q], k++]; q, {n, 3, 100}]
(* JeanFrançois Alcover, Apr 26 2011 *)


PROG

(Haskell)
a002373 n = head $ dropWhile ((== 0) . a010051 . (2*n )) a065091_list
 Reinhard Zumkeller, Feb 29 2012
(PARI) a(n)=forprime(p=3, n, if(isprime(2*np), return(p))) \\ Charles R Greathouse IV, May 18 2015


CROSSREFS

Cf. A002372, A002374, A014092, A065091, A010051.
Sequence in context: A084742 A242033 A049613 * A236569 A103153 A162022
Adjacent sequences: A002370 A002371 A002372 * A002374 A002375 A002376


KEYWORD

nonn,nice,easy


AUTHOR

N. J. A. Sloane.


EXTENSIONS

More terms from Ray Chandler, Sep 19 2003


STATUS

approved



