A230035 Numbers which can be represented as a sum of 3 relatively prime positive integers such that each pair of them is not coprime.

31, 37, 41, 43, 47, 49, 53, 55, 59, 61, 65, 67, 69, 71, 73, 77, 79, 83, 85, 86, 87, 89, 91, 92, 93, 95, 97, 99, 101, 103, 106, 107, 109, 111, 113, 115, 116, 117, 118, 119, 121, 122, 123, 125, 127, 128, 129, 131, 133, 134, 135, 136, 137, 139, 141, 143

Offset

1,1

Comments

The complement of A230034.

Each number beginning from 2731 is in a(n).

Generally for every positive integer k there is only finite quantity of numbers which can't be represented as a sum of k+1 relatively prime positive integers such that any k of them are not coprime.

For instance, for k = 3 570570 is the largest number which cannot be represented.

Links

Table of n, a(n) for n=1..56.

Example

31 is in a(n) because 31 = 6 + 10 + 15  and gcd(6, 10, 15) = 1 however gcd(6, 10) = 2, gcd(6, 15) = 3,  gcd(10, 15) = 5.

Crossrefs

Cf. A230034, A284825.

Sequence in context: A053684 A336178 A044973 * A051267 A073521 A180540

Adjacent sequences: A230032 A230033 A230034 * A230036 A230037 A230038

Keyword

nonn

Author

Vladimir Letsko, Dec 20 2013

Status

approved