A262983 Terms of A005179 divisible by their indices in order of appearance in A005179.

1, 2, 12, 24, 36, 60, 180, 240, 360, 720, 1260, 1680, 3600, 6720, 5040, 10080, 32400, 15120, 20160, 25200, 60480, 55440, 810000, 100800, 181440, 110880, 226800, 221760, 277200, 907200, 665280, 1587600, 720720, 5670000, 1108800, 3548160, 1995840, 1441440, 2494800, 6350400

Offset: 1

Author

Vladimir Letsko, Oct 06 2015

Keywords

• nonn
• look

Comments

A005179(n) is in this sequence iff it is divisible by n. Thus this is a subsequence of A005179 indexed by A262981.

Also this sequence is the intersection of A033950 and A005179. Hence this sequence has density zero. - Vladimir Letsko, Dec 16 2016

It seems that this sequence is a subsequence of A262981.

This sequence is not in ascending order as terms of A005179 divisible by their number of divisors do not occur in ascending order. For terms sorted in ascending order see A110821. - David A. Corneth, Dec 10 2021

Examples

			12 is a term since it is the smallest positive integer having exactly 6 divisors and divisible by 6.
		

Links

• David A. Corneth, Table of n, a(n) for n = 1..10000
• Vladimir Letsko, The table of correspondence between A262983 and A262981

Crossrefs

Cf. A000005, A033950, A005179, A110821, A262981, A279373.

Programs

Mathematica

Take[#, 33] &@ DeleteCases[#, 0] &@ Function[s, ReplacePart[#, Flatten@ Map[{# -> Function[k, k Boole[Divisible[k, #]]]@ Lookup[s, #]} &, Keys@ s]] &@ ConstantArray[0, Max@ Keys@ s]]@ Map[First, KeySort@ PositionIndex@ Table[DivisorSigma[0, n], {n, 10^7}]] (* Michael De Vlieger, Dec 11 2016, Version 10 *)

Formula

a(n) = A005179(A262981(n)).

A000005(a(n)) = A262981(n).

Extensions

Name clarified by David A. Corneth, Dec 10 2021