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A109730
Lesser of twin admirable numbers: k such that k and k+2 are both admirable numbers.
3
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
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
KEYWORD
nonn
AUTHOR
Jason Earls, Aug 09 2005
STATUS
approved