This site is supported by donations to The OEIS Foundation.

 Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS". Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A066615 Numbers that are not the sum of two or three distinct primes. 1
 1, 2, 3, 4, 6, 11, 17 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Probably there are no further terms. An outgrowth of Goldbach's conjecture. "[I]n a letter to L. Euler (1742), C. F. Goldbach [asserted] that 'every odd number greater than 6 is equal to the sum of three primes.' Euler replied that Goldbach's conjecture was equivalent to the statement that every even number equal to or greater than 4 is equal to the sum of two primes. Because proving the second implies the first, but not the converse, most attention has been focused on the second representation. However, whether the statement is true for all even integers is still unsettled. Nevertheless, it is supported by existing evidence. A Russian mathematician, I. M. Vinogradov, proved that all large odd integers are the sum of three primes. Surprisingly, his techniques involve extremely subtle use of the theory of complex variables; no one has been able to extend them in order to solve Goldbach's conjecture." Andrews. "Every number greater than 17 is the sum of 3 integers greater than 1 which are relatively prime in pairs." - Wells. REFERENCES George E. Andrews, "Number Theory," Dover Publ. Inc., NY, 1994, page 111. Calvin C. Clawson, "Mathematical Mysteries, the beauty and magic of numbers," Perseus Books, Cambridge, MA, 1996, Chapter 12, Pages 236-257. Mark Herkommer, "Number Theory, A Programmer's Guide," McGraw-Hill, NY, 1999, pages 359-362. Ivan Niven, Herbert S. Zuckerman and Hugh L. Montgomery, "An Introduction to The Theory of Numbers," Fifth Edition, John Wiley & Sons, Inc. NY, 1991, page 2. Wacław Sierpiński, "250 Problems in Elementary Number Theory," New York: American Elsevier, Warsaw, 1970, pp. 4, 38-39. David Wells, "The Penguin Dictionary of Curious and Interesting Numbers," Revised Edition, Penguin Books, London, 1997, page 76. LINKS MATHEMATICA a = Table[ Prime[n], {n, 1, 100}]; b = {0}; Do[ b = Append[b, a[[i]] + a[[j]]], {j, 2, 100}, {i, 1, j - 1}]; Union[b]; c = {0}; Do[ c = Append[c, a[[i]] + a[[j]] + a[[k]]], {k, 3, 100}, {j, 2, k - 1}, {i, 1, j - 1}]; Union[c]; Complement[ Table[n, {n, 1, 541} ], Union[b, c]] CROSSREFS Intersection of A166081 and A124868. Sequence in context: A050886 A079310 A116853 * A133951 A166081 A111124 Adjacent sequences:  A066612 A066613 A066614 * A066616 A066617 A066618 KEYWORD fini,nonn AUTHOR Amarnath Murthy, Dec 24 2001 EXTENSIONS Entry revised by Robert G. Wilson v, Dec 27 2001 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.