

A306871


Larger of reduced biunitary amicable pair.


2



2295, 20735, 75495, 1148735, 817479, 774375, 1902215, 1341495, 1348935, 2226014, 2421704, 3123735, 3010215, 5644415, 3894344, 4282215, 4994055, 7509159, 12251679, 10106504, 12900734, 20444319, 24519159, 28206815, 31356314, 33362175, 41950359, 36129375, 43321095
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OFFSET

1,1


COMMENTS

A pair m < n are a reduced biunitary amicable pair if bsigma(m) = bsigma(n) = m + n + 1, where bsigma(n) is the sum of biunitary divisors of n (A188999).
The terms are ordered according to their lesser counterparts (A306870).


LINKS



EXAMPLE

2295 is in the sequence since it is the larger of the amicable pair (2024, 2295): bsigma(2024) = bsigma(2295) = 4320 = 2024 + 2295 + 1.


MATHEMATICA

fun[p_, e_]:=If[OddQ[e], (p^(e+1)1)/(p1), (p^(e+1)1)/(p1)p^(e/2)]; bsigma[1] = 1; bsigma[n_] := Times @@ (fun @@@ FactorInteger[n]); f[n_] := bsigma[n]  n  1; s={}; Do[m = f[n]; If[m > n && f[m] == n, AppendTo[s, m]], {n, 1, 10^7}]; s


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



