login
A061671
Numbers n such that { x +- 2^k : 0 < k < 4 } are primes, where x = 210*n - 105.
4
1, 77, 93, 209, 5197, 7695, 9307, 13442, 13524, 15445, 16192, 28600, 30970, 34228, 36388, 38391, 41625, 50127, 52795, 55546, 69146, 70538, 70642, 70747, 76314, 76642, 90079, 91416, 93496, 94288, 95773, 96415, 101530, 104049, 107559, 118031
OFFSET
1,2
COMMENTS
This sequence does not include the sextet (7,11,13,17,19,23). It is a proper subset of A014561 in a certain sense.
REFERENCES
G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers, 5th ed., Oxford Univ. Press, 1979, conjectures following th. 5
EXAMPLE
16057, 16061, 16063, 16067, 16069, 16073 are prime and (16065+105)/210= 77= a(2).
MATHEMATICA
Select[Range[1, 1000000], Union[PrimeQ[(210*# - 105) + {-8, -4, -2, 2, 4, 8}]] == {True} &]
Select[Range[120000], AllTrue[210#-105+{-8, -4, -2, 2, 4, 8}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 05 2019 *)
CROSSREFS
210 = 7*5*3*2 = A002110(4), cf. A014561.
Sequence in context: A052202 A089525 A274172 * A269809 A064902 A247682
KEYWORD
nonn
AUTHOR
Frank Ellermann, Jun 16 2001
EXTENSIONS
More terms from Larry Reeves (larryr(AT)acm.org), Jun 20 2001 and from Frank Ellermann, Nov 26 2001. Mathematica script from Peter Bertok (peter(AT)bertok.com), Nov 27 2001.
STATUS
approved