A294029 Values of bsigma(k) = bsigma(k+1), where bsigma is the sum of the bi-unitary divisors (A188999).

24, 40, 60, 720, 960, 1440, 2160, 2640, 2400, 3000, 4320, 4320, 4320, 5280, 7400, 11520, 11880, 12960, 14400, 20160, 30240, 26640, 34560, 25200, 34560, 49920, 51840, 60480, 63360, 60480, 65280, 62400, 61560, 115200, 93600, 114912, 100800, 120960, 120960

Offset: 1

Author

Amiram Eldar, Oct 22 2017

Keywords

• nonn

Comments

The sum of bi-unitary divisors of numbers n such that n and n+1 have the same sum (A293183).

The bi-unitary version of A053215.

Examples

			24 is in the sequence since 24 = bsigma(14) = bsigma(15).
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..2148

Crossrefs

Cf. A053215, A290303, A188999, A293183.

Programs

Mathematica

f[n_] := Select[Divisors[n], Function[d, CoprimeQ[d, n/d]]]; bsigma[m_] := DivisorSum[m, # &, Last@Intersection[f@#, f[m/#]] == 1 &]; a = {}; b1 = 0; For[k = 0, k < 10^6, k++; b2 = bsigma[k]; If[b1 == b2, a = AppendTo[a, b1]]; b1 = b2]; a (* after Michael De Vlieger at A188999 *)

Formula

a(n) = A188999(A293183(n)).