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 A067187 Numbers that can be expressed as the sum of two primes in exactly one way. 10
 4, 5, 6, 7, 8, 9, 12, 13, 15, 19, 21, 25, 31, 33, 39, 43, 45, 49, 55, 61, 63, 69, 73, 75, 81, 85, 91, 99, 103, 105, 109, 111, 115, 129, 133, 139, 141, 151, 153, 159, 165, 169, 175, 181, 183, 193, 195, 199, 201, 213, 225, 229, 231, 235, 241, 243, 253, 259, 265, 271 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All primes + 2 are terms of this sequence. Is 12 the last even term? - Frank Ellermann, Jan 17 2002 A048974, A052147, A067187 and A088685 are very similar after dropping terms less than 13. - Eric W. Weisstein, Oct 10 2003 Values of n such that A061358(n)=1. - Emeric Deutsch, Apr 03 2006 LINKS EXAMPLE 4 is a term as 4 = 2+2, 15 is a term as 15 = 13+2. MAPLE g:=sum(sum(x^(ithprime(i)+ithprime(j)), i=1..j), j=1..80): gser:=series(g, x=0, 280): a:=proc(n) if coeff(gser, x^n)=1 then n else fi end: seq(a(n), n=1..272); # Emeric Deutsch, Apr 03 2006 MATHEMATICA cQ[n_]:=Module[{c=0}, Do[If[PrimeQ[n-i]&&PrimeQ[i], c++], {i, 2, n/2}]; c==1]; Select[Range[4, 271], cQ[#]&] (* Jayanta Basu, May 22 2013 *) CROSSREFS Cf. A023036, A067188-A067191, A066722, A045917, A061358. Subsequence of A014091. Cf. A061358. Sequence in context: A321025 A047569 A039062 * A321353 A161674 A285623 Adjacent sequences:  A067184 A067185 A067186 * A067188 A067189 A067190 KEYWORD nonn AUTHOR Amarnath Murthy, Jan 10 2002 EXTENSIONS Edited by Frank Ellermann, Jan 17 2002 STATUS approved

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Last modified August 13 05:41 EDT 2020. Contains 336442 sequences. (Running on oeis4.)