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A101984 Numbers that occur exactly once in A101909 (= count of primes between 2n and 4n). 2
1, 3, 5, 8, 22, 36, 37, 46, 47, 48, 53, 63, 83, 98, 99, 101, 105, 108, 113, 114, 127, 135, 139, 148, 150, 155, 158, 171, 172, 173, 174, 175, 177, 178, 188, 205, 210, 218, 219, 220, 221, 226, 231, 240, 246, 254, 277, 282, 297, 298, 301, 303, 327, 333, 334, 339 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
EXAMPLE
There are 5 primes between 16 and 32 and nowhere else between 2n and 4n.
PROG
(PARI) bet2n4n(n)={ my(b=vecsort(vector(n, x, my(c=0); forprime(y=2*x+1, 4*x-1, c++); c))); print1(1", "); for(x=1, n-2, if(b[x+1]>b[x] && b[x+1]<b[x+2], print1(b[x+1]", ")))} \\ Edited and corrected, following a suggestion by Don Reble. - M. F. Hasler, Sep 29 2019
CROSSREFS
Sequence in context: A141615 A075192 A361089 * A292492 A108460 A249951
KEYWORD
easy,nonn
AUTHOR
Cino Hilliard, Jan 28 2005
EXTENSIONS
Better name from N. J. A. Sloane, Sep 29 2019
Corrected a(22) and a(45), following an observation by Don Reble. - M. F. Hasler, Sep 29 2019
STATUS
approved

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Last modified March 28 05:02 EDT 2024. Contains 371235 sequences. (Running on oeis4.)