A344313 Number k such that k and k+1 have the same number of bi-unitary divisors (A286324).

2, 3, 4, 14, 15, 20, 21, 26, 27, 33, 34, 35, 38, 44, 45, 50, 51, 57, 62, 68, 74, 75, 76, 81, 85, 86, 91, 92, 93, 94, 98, 99, 104, 115, 116, 117, 118, 122, 123, 124, 133, 135, 141, 142, 145, 146, 147, 158, 171, 177, 187, 189, 201, 202, 205, 206, 212, 213, 214

Offset

1,1

Links

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

Example

2 is a term since A286324(2) = A286324(3) = 2.
14 is a term since A286324(14) = A286324(15) = 4.

Mathematica

f[p_, e_] := If[OddQ[e], e + 1, e]; bd[1] = 1; bd[n_] := Times @@ f @@@ FactorInteger[n]; Select[Range[200], bd[#] == bd[# + 1] &]

Crossrefs

Cf. A286324, A293183, A304463.

Similar sequences: A005237, A006049, A343819, A344312, A344314.

Sequence in context: A039576 A091907 A354075 * A103048 A343819 A140128

Adjacent sequences: A344310 A344311 A344312 * A344314 A344315 A344316

Keyword

nonn

Author

Amiram Eldar, May 14 2021

Status

approved