A094520 Numbers such that all sums of two distinct divisors are not divisors.

1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 21, 22, 23, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 37, 38, 39, 41, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 55, 57, 58, 59, 61, 62, 63, 64, 65, 67, 68, 69, 71, 73, 74, 75, 76, 77, 79, 81, 82, 83, 85, 86, 87, 88, 89, 91

Offset

1,2

Links

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

Eric Weisstein's World of Mathematics, Sum-Free Set

Formula

A094518(a(n)) = 0.

Mathematica

aQ[n_] := AllTrue[Total /@ Subsets[Divisors[n], {2}], ! Divisible[n, #] &]; Select[Range[91], aQ] (* Amiram Eldar, Aug 31 2019 *)

Crossrefs

Cf. A094518.

Complement of A094519.

Sequence in context: A364347 A228869 A088725 * A136447 A005100 A051772

Adjacent sequences: A094517 A094518 A094519 * A094521 A094522 A094523

Keyword

nonn

Author

Reinhard Zumkeller, May 06 2004

Status

approved