|
Search: id:A038133
|
|
|
| A038133 |
|
From a subtractive Goldbach conjecture: odd primes that are not cluster primes. |
|
+0
5
|
|
| 97, 127, 149, 191, 211, 223, 227, 229, 251, 257, 263, 269, 293, 307, 331, 337, 347, 349, 367, 373, 379, 383, 397, 409, 419, 431, 457, 479, 487, 499, 521, 541, 547, 557, 563, 569, 587, 593, 599, 631, 641, 673, 691, 701, 709, 719, 727, 733, 739, 743, 751
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Erdos asks if there are infinitely many primes p such that every even number <= p-3 can be expressed as the difference between two primes each <= p. Sequence gives primes not having this property.
|
|
REFERENCES
|
R. Blecksmith et al., Cluster primes, Amer. Math. Monthly, 106 (1999), 43-48.
R. K. Guy, Unsolved Problems In Number Theory, section C1.
|
|
LINKS
|
T. D. Noe, Table of n, a(n) for n=1..10000
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
Index entries for sequences related to Goldbach conjecture
|
|
MATHEMATICA
|
m=1000; lst={}; n=PrimePi[m]-1; p=Table[Prime[i+1], {i, n}]; d=Table[0, {m/2}]; For[i=2, i<=n, i++, For[j=1, j<i, j++, diff=p[[i]]-p[[j]]; d[[diff/2]]++ ]; c=Count[Take[d, (p[[i]]-3)/2], 0]; If[c>0, AppendTo[lst, p[[i]]]]]; lst
|
|
CROSSREFS
|
Cf. A038134, A039506, A039507, A072325.
Adjacent sequences: A038130 A038131 A038132 this_sequence A038134 A038135 A038136
Sequence in context: A033202 A136477 A078494 this_sequence A073076 A000923 A139500
|
|
KEYWORD
|
nonn,easy,nice
|
|
AUTHOR
|
njas
|
|
EXTENSIONS
|
More terms from Christian G. Bower (bowerc(AT)usa.net), Feb 15 1999.
|
|
|
Search completed in 0.002 seconds
|
