A192818 Numbers which are both deficient (A005100) and anti-deficient (A192267).

1, 2, 3, 4, 9, 16, 19, 26, 29, 34, 44, 51, 61, 64, 69, 79, 89, 106, 131, 134, 139, 141, 146, 159, 166, 169, 191, 194, 201, 209, 211, 219, 226, 236, 239, 244, 251, 254, 261, 271, 274, 289, 296, 299, 309, 316, 321, 334, 339, 341, 344, 349, 359, 376, 381, 386

Offset: 1

Author

Jonathan Vos Post, Jul 10 2011

Keywords

• nonn
• easy

Examples

			24 is anti-deficient because its anti-divisors are 7, 16 and their sum is 23 < 24.  26 is deficient because its proper divisors are 1, 2, 13 which sum to 16 and 16 < 26.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1500 from Nathaniel Johnston)

Crossrefs

Cf. A005100, A066417, A192267.

Programs

Mathematica

q[n_] := Total[Cases[Range[2, n - 1], ?(Abs[Mod[n, #] - #/2] < 1 &)]] < n && DivisorSigma[1, n] < 2*n; Select[Range[300], q] (* _Amiram Eldar, Jan 13 2022 after Michael De Vlieger at A066417 *)

Formula

A005100 INTERSECTION A192267.

Extensions

More terms and inserted a(1)=1 from Nathaniel Johnston, Sep 26 2011