A283418 Numbers n such that n and n+1 are primitive abundant.

82004, 158235, 326864, 442035, 516704, 1102724, 1606275, 2151435, 2697435, 2912084, 2921535, 2979675, 3002804, 3241755, 3647475, 4322835, 5801984, 5905844, 6069195, 7251075, 7387604, 7553924, 8272124, 8788724, 9292724, 9909584

Offset: 1

Author

Emmanuel Vantieghem, May 02 2017

Keywords

• nonn

Comments

Intersection of A091191 and -1 + A091191.

Examples

			82004 is in the sequence because it is abundant (sum divisors = 164640, > 2*82004) and 82005 is also abundant (sum divisors = 165888, > 2*82005).
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A091191, A005105, A096399.

Programs

Mathematica

fQ[m_] := DivisorSigma[1, m] > 2 m;
gQ[m_] := fQ[m] && Union[fQ /@ Rest[Most[Divisors[m]]]] == {False};
V = Select[Range[10^7], gQ]; Intersection[V, V - 1]