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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

LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000

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

Cf. A038511, A084969, A084970.

Cf. A287391.

Sequence in context: A184046 A235810 A229906 * A287934 A152852 A156572

Adjacent sequences:  A008364 A008365 A008366 * A008368 A008369 A008370

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified June 1 03:14 EDT 2020. Contains 334758 sequences. (Running on oeis4.)