login
A067199
Integers k such that k*28*c + 1 is prime for c = 1, 2, 4, 7 and 14.
3
2136, 2211, 4071, 5106, 5430, 9000, 10656, 17655, 18315, 20220, 20805, 21381, 22356, 22920, 23025, 29616, 37050, 39261, 45795, 49920, 55686, 60435, 62205, 64380, 79356, 81345, 91455, 94800, 95910, 96285, 105336, 108585, 111885, 118626
OFFSET
1,1
COMMENTS
The product of the 5 primes is a Carmichael number. 28=1+2+4+7+14.
REFERENCES
H. Davenport, The Higher Arithmetic. Cambridge Univ. Press, 7th ed., 1999, exercise 8.4.
LINKS
EXAMPLE
2136 results in Carmichael number 599966117492747584686619009.
MATHEMATICA
aQ[n_] := AllTrue[{1, 2, 4, 7, 14}, PrimeQ[28 * n * # + 1] &]; Select[Range[10^5], aQ] (* Amiram Eldar, Sep 19 2019 *)
CROSSREFS
Cf. A002997, A046025 (based on 6 instead of 28, exercise 8.3 in Davenport), A112428.
Sequence in context: A260068 A237070 A157768 * A064249 A206007 A233229
KEYWORD
nonn,easy
AUTHOR
Frank Ellermann, Feb 19 2002
EXTENSIONS
Offset corrected by Amiram Eldar, Sep 19 2019
STATUS
approved