A329187 Initial members of admirable triples: numbers k such that (k, k+2, k+4) are all admirable numbers (A111592).

364, 17272, 54064, 383404, 1820812, 1945804, 2466604, 3283024, 3503164, 3820684, 3907984, 4407952, 5553712, 6095344, 6320524, 6820492, 7845232, 7966252, 8591212, 9841132, 10990864, 11841004, 12428272, 13695052, 13903372, 15032272, 15569932, 19007212, 19740304

Offset

1,1

Links

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

Example

364 is in the sequence since 364, 366, and 368 are all admirable numbers.

Mathematica

admQ[n_] := (ab = DivisorSigma[1, n] - 2 n) > 0 && EvenQ[ab] && ab/2 < n && Divisible[n, ab/2]; k = 0; s = {}; Do[If[admQ[n], k++; If[k > 2, AppendTo[s, n - 4]], k = 0], {n, 6, 2*10^6, 2}]; s (* for even terms; after Shyam Sunder Gupta at A231088 *)

Crossrefs

Subsequence of A109730, A111592, and A231088.

Sequence in context: A175114 A022045 A278002 * A107509 A140935 A249671

Adjacent sequences: A329184 A329185 A329186 * A329188 A329189 A329190

Keyword

nonn

Author

Amiram Eldar, Nov 07 2019

Status

approved