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
Amiram Eldar, Table of n, a(n) for n = 1..10000
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
KEYWORD
nonn,easy
AUTHOR
Frank Ellermann, Feb 19 2002
EXTENSIONS
Offset corrected by Amiram Eldar, Sep 19 2019
STATUS
approved