|
| |
|
|
A101984
|
|
Numbers that occur only once in the count of primes between 2n and 4n.
|
|
1
| |
|
|
1, 3, 5, 8, 22, 36, 37, 46, 47, 48, 53, 63, 83, 98, 99, 101, 105, 108, 113, 114, 127, 134, 139, 148, 150, 155, 158, 171, 172, 173, 174, 175, 177, 178, 188, 205, 210, 218, 219, 220, 221, 226, 231, 240, 245, 254, 277, 282, 297, 298, 301, 303, 327, 333, 334, 339
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
EXAMPLE
| There are 5 primes between 16 and 32 and nowhere else between 2n and 4n.
|
|
|
PROG
| (PARI) bet2n4n(n) = { local(c, c1, x, y); a=vector(10002); for(x=1, n, c=0; forprime(y=2*x+1, 4*x-1, c++; ); a[x] = c; ); b=vecsort(a); print1(1", "); for(x=1, 10000, if(b[x]>0, if(b[x+1]<>b[x]&b[x+1]<>b[x+2], print1(b[x]+1", ") ) ); ) }
|
|
|
CROSSREFS
| Cf. A101909, A101947, A101983. A101985.
Sequence in context: A002366 A141615 A075192 * A108460 A027520 A195548
Adjacent sequences: A101981 A101982 A101983 * A101985 A101986 A101987
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Cino Hilliard (hillcino368(AT)gmail.com), Jan 28 2005
|
| |
|
|
