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A292980
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Smaller of bi-unitary amicable pair.
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7
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114, 594, 1140, 3608, 4698, 5940, 6232, 7704, 9520, 10744, 12285, 13500, 41360, 44772, 46980, 60858, 62100, 67095, 67158, 73360, 79650, 79750, 105976, 118500, 141664, 142310, 177750, 185368, 193392, 217840, 241024, 298188, 308220, 308992, 356408, 399200
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OFFSET
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1,1
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COMMENTS
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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 larger members are in A292981.
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LINKS
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Amiram Eldar, Table of n, a(n) for n = 1..6368 (all terms 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.
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EXAMPLE
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3608 is in the sequence since A188999(3608) - 3608 = 3952 and A188999(3952) - 3952 = 3608.
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MATHEMATICA
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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[n]], {n, 1, 10000}] (* Amiram Eldar, Sep 29 2018 *)
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CROSSREFS
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Cf. A002025, A188999, A292981.
Sequence in context: A122279 A251481 A251475 * A126169 A324708 A251459
Adjacent sequences: A292977 A292978 A292979 * A292981 A292982 A292983
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KEYWORD
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nonn
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AUTHOR
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Amiram Eldar, Sep 27 2017
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STATUS
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approved
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