|
|
A008367
|
|
Composite but smallest prime factor >= 17.
|
|
3
|
|
|
289, 323, 361, 391, 437, 493, 527, 529, 551, 589, 629, 667, 697, 703, 713, 731, 779, 799, 817, 841, 851, 893, 899, 901, 943, 961, 989, 1003, 1007, 1037, 1073, 1081, 1121, 1139, 1147, 1159, 1189, 1207, 1219, 1241, 1247, 1271, 1273, 1333, 1343, 1349, 1357, 1363, 1369, 1387, 1403, 1411, 1457
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Composite numbers k such that k^720 mod 30030 = 1. - Gary Detlefs, May 02 2012
The asymptotic density of this sequence is 192/1001. - Amiram Eldar, Mar 22 2021
|
|
LINKS
|
|
|
FORMULA
|
For 1 <= n < 107, a(n) = A287391(n+2); then a(107) = 2329, a(108) = 2363 are not in A287391, but again a(n) = A287391(n) for 108 < n < 120. - M. F. Hasler, Oct 04 2018
|
|
MAPLE
|
for i from 1 to 2000 do if gcd(i, 30030) = 1 and not isprime(i) then print(i); fi; od;
|
|
MATHEMATICA
|
Select[ Range[ 1500 ], (GCD[ #1, 30030 ]==1&&!PrimeQ[ #1 ])& ]
Select[Range[2000], ! PrimeQ[#] && FactorInteger[#][[1, 1]] >= 17 &] (* T. D. Noe, Mar 16 2013 *)
|
|
PROG
|
(PARI) is(n)={gcd(n, 30030)==1 && !ispseudoprime(n)} \\ M. F. Hasler, Oct 04 2018
(GAP) Filtered([17..1500], n->PowerMod(n, 720, 30030)=1 and not IsPrime(n)); # Muniru A Asiru, Nov 24 2018
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|