|
Search: id:A007921
|
|
|
| A007921 |
|
Numbers that are not the difference of two primes. |
|
+0
9
|
|
| 7, 13, 19, 23, 25, 31, 33, 37, 43, 47, 49, 53, 55, 61, 63, 67, 73, 75, 79, 83, 85, 89, 91, 93, 97, 103, 109, 113, 115, 117, 119, 121, 123, 127, 131, 133, 139, 141, 143, 145, 151, 153, 157, 159, 163, 167, 169, 173, 175, 181, 183, 185, 187, 193
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
REFERENCES
|
F. Smarandache, Properties of Numbers, 1972. (See Smarandache odd sieve.)
F. Smarandache, "Only Problems, not Solutions!", Xiquan Publ., Phoenix-Chicago, 1993
|
|
LINKS
|
T. D. Noe, Table of n, a(n) for n=1..10000
C. Dumitrescu & V. Seleacu, editors, Some Notions and Questions in Number Theory, Vol. I.
F. Smarandache, Only Problems, Not Solutions!
Index entries for primes, gaps between
|
|
FORMULA
|
Odd numbers n such that n+2 is composite.
|
|
CROSSREFS
|
Cf. A048859.
Complement of A030173. Cf. A001223.
Equals A005381(2n-1) - 1.
Sequence in context: A074628 A031194 A121058 this_sequence A092409 A124095 A109369
Adjacent sequences: A007918 A007919 A007920 this_sequence A007922 A007923 A007924
|
|
KEYWORD
|
nonn,easy,nice
|
|
AUTHOR
|
R. Muller
|
|
|
Search completed in 0.002 seconds
|
