A134335 Numbers such that the arithmetic mean of their prime factors (counted with multiplicity) is integer, but not prime.

15, 35, 39, 42, 50, 51, 55, 65, 77, 78, 87, 91, 92, 95, 110, 111, 114, 115, 119, 123, 140, 141, 143, 155, 159, 161, 164, 170, 183, 185, 186, 187, 189, 201, 203, 204, 209, 215, 219, 221, 222, 225, 230, 235, 236, 242, 247, 258, 259, 264, 267, 284, 285, 287, 290

Offset

1,1

Links

Hieronymus Fischer, Table of n, a(n) for n = 1..10000

Example

a(1) = 15, since 15 = 3*5 and (3+5)/2 = 4 is not prime.
a(5) = 50, since 50 = 2*5*5 and (2+5+5)/3 = 4 is not prime.

Crossrefs

Cf. A000040, A001222, A100118, A046363, A133620, A133621.

Cf. A133880, A133890, A133900, A133910, A133911, A046346, A134331, A134332, A134333, A134334.

Sequence in context: A253055 A338063 A111170 * A257591 A284406 A329589

Adjacent sequences: A134332 A134333 A134334 * A134336 A134337 A134338

Keyword

nonn

Author

Hieronymus Fischer, Oct 23 2007

Extensions

Definition clarified by the author, May 06 2013

Status

approved