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A292981 Larger of bi-unitary amicable pair. 7
126, 846, 1260, 3952, 5382, 8460, 6368, 8496, 13808, 10856, 14595, 17700, 51952, 49308, 53820, 83142, 62700, 71145, 73962, 97712, 107550, 88730, 108224, 131100, 153176, 168730, 196650, 203432, 195408, 287600, 309776, 306612, 365700, 332528, 399592, 419800 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Analogous to amicable numbers with bi-unitary sigma (A188999) instead of sigma (A000203).

Hagis found all the bi-unitary amicable pairs with smaller members below 10^6.

The smaller members are in A292980.

The terms are ordered according to their lesser counterparts.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..6368 (all terms with lesser member below 2*10^11, from David Moews' site).

Peter Hagis, Jr., Bi-unitary amicable and multiperfect numbers, Fibonacci Quarterly, Vol. 25, No. 2 (1987), pp. 144-150.

David Moews, Perfect, amicable and sociable numbers.

EXAMPLE

3952 is in the sequence since A188999(3608) - 3608 = 3952 and A188999(3952) - 3952 = 3608.

MATHEMATICA

fun[p_, e_]:=If[Mod[e, 2]==1, (p^(e+1)-1)/(p-1), (p^(e+1)-1)/(p-1)-p^(e/2)];

bsigma[n_] := If[n==1, 1, Times @@ (fun @@@ FactorInteger[n])]; Do[s = bsigma[n]; If[s > 2 n && bsigma[s - n] == s, Print[s-n]], {n, 1, 10000}] (* Amiram Eldar, Sep 29 2018 *)

CROSSREFS

Cf. A002046, A188999, A292980.

Sequence in context: A107658 A181254 A004008 * A126170 A324709 A342307

Adjacent sequences:  A292978 A292979 A292980 * A292982 A292983 A292984

KEYWORD

nonn

AUTHOR

Amiram Eldar, Sep 27 2017

STATUS

approved

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Last modified April 15 12:55 EDT 2021. Contains 342977 sequences. (Running on oeis4.)