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A199595
Numbers n such that 3n+6, 3n+7 and 3n+8 are all composite.
1
1, 4, 9, 11, 14, 18, 21, 23, 24, 31, 32, 33, 34, 37, 40, 41, 44, 46, 49, 51, 54, 55, 60, 61, 62, 64, 65, 66, 71, 74, 75, 77, 79, 81, 84, 88, 89, 91, 92, 93, 94, 99, 100, 101, 102, 104, 106, 107, 111, 113, 114, 116, 118, 121, 123, 124, 127, 128, 130, 131, 134, 135, 138, 141, 143, 144, 149, 150, 151, 153, 154, 157, 158, 161, 163, 164, 165, 168, 169, 170
OFFSET
1,2
REFERENCES
Ernest V. Miliauskas, letter to N. J. A. Sloane, Dec 21 1985.
FORMULA
a(n) = A199593(n)-8.
PROG
(PARI) is(n)=!isprime(bitor(3*n+7, 1)) \\ Charles R Greathouse IV, Jul 03 2013
CROSSREFS
Sequence in context: A010438 A357474 A005241 * A028845 A050626 A050627
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Nov 08 2011
STATUS
approved