A116661 -id:A116661 - cp's OEIS frontend

A116660 Integers in both sequences A075658 and A067028.

56, 60, 84, 90, 104, 126, 132, 135, 140, 150, 152, 156, 184, 189, 196, 198, 204, 220, 224, 225, 228, 234, 240, 248, 260, 276, 294, 296, 297, 306, 308, 315, 330, 336, 340, 342, 344, 348, 350, 351, 360, 364, 372, 375, 376, 380, 414, 416, 424, 441, 444, 459

Offset: 1

Leroy Quet, Feb 21 2006

nonn

It could be argued that 1 should also be included in the sequence, if 0 is considered to be a composite, since the number of prime divisors (counted with multiplicity) of 1 and the sum of 1's distinct prime divisors are both 0.

			60 = 2^2 *3^1 *5^1. Both the number of prime divisors (counted with multiplicity), 2+1+1 = 4 and the sum of the distinct prime divisors, 2+3+5 = 10, are composite. So 60 is in the sequence.

Amiram Eldar, Table of n, a(n) for n = 1..10000

Cf. A075658, A067028, A116661.

Select[Range[460], CompositeQ[Plus @@ (f = FactorInteger[#])[[;; , 1]]] && CompositeQ[Plus @@ f[[;; , 2]]] &] (* Amiram Eldar, Nov 14 2019 *)

More terms from R. J. Mathar, Aug 31 2007

cp's OEIS Frontend

A116660 Integers in both sequences A075658 and A067028.

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