A166070 Sorted sequence of primes and multiply perfect numbers.

1, 2, 3, 5, 6, 7, 11, 13, 17, 19, 23, 28, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 120, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263

Offset: 1

Author

Jaroslav Krizek, Oct 06 2009, Oct 16 2009

Keywords

• nonn

Comments

Numbers k such that sigma(k) is divisible by all proper divisors of k.

Examples

			a(4) = 6: all proper divisors of 6 (1, 2, 3) divide sigma(6) = 12.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A053813.

Programs

Mathematica

Select[Range[300],And@@Divisible[DivisorSigma[1,#],Most[Divisors[#]]]&] (* Harvey P. Dale, Jan 18 2015 *)

Formula

A000040 Union A007691.

{1} Union A053813 Union A166069.

{1} Union A000040 Union A000396 Union A166069.