A109730 Lesser of twin admirable numbers: k such that k and k+2 are both admirable numbers.

40, 54, 102, 138, 222, 364, 366, 474, 532, 642, 834, 1036, 1146, 1372, 1504, 1876, 1986, 2994, 3052, 3556, 4396, 4564, 5514, 5572, 5622, 6198, 6412, 6522, 7026, 7912, 7924, 8202, 8596, 8706, 9424, 9714, 10444, 10722, 11226, 11406, 12066, 12964

Offset

1,1

Comments

Conjecture: Sequence is infinite.

Links

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

Mathematica

Select[Range[13000], MemberQ[Most[Divisors[#]], (DivisorSigma[1, #]-2*#)/2] && MemberQ[Most[Divisors[#+2]], (DivisorSigma[1, #+2]-2*(#+2))/2]&] (* James C. McMahon, Mar 29 2024 *)

Crossrefs

Cf. A111592.

Sequence in context: A110227 A108607 A356744 * A100333 A372298 A349242

Adjacent sequences: A109727 A109728 A109729 * A109731 A109732 A109733

Keyword

nonn

Author

Jason Earls, Aug 09 2005

Status

approved