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

Author

Jason Earls, Aug 09 2005

Keywords

• nonn

Comments

Conjecture: Sequence is infinite.

Links

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

Crossrefs

Cf. A111592.

Programs

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 *)