A199595 Numbers n such that 3n+6, 3n+7 and 3n+8 are all composite.

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.

Links

Table of n, a(n) for n=1..80.

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

Adjacent sequences: A199592 A199593 A199594 * A199596 A199597 A199598

Keyword

nonn,easy

Author

N. J. A. Sloane, Nov 08 2011

Status

approved