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A180202
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The product of the two numbers in an amicable pair, A002025(n) * A002046(n).
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4
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62480, 1432640, 7660880, 27931280, 39685376, 116636864, 179299575, 318523136, 4794813680, 4483640576, 4773473775, 6100571295, 7076217500, 12475715175, 17094480975, 15069863936, 21699524864, 24011966300, 30304399616
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OFFSET
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1,1
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COMMENTS
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This sequence initially shares many terms with A180163 because small amicable pairs are sometimes consecutive terms in the sorted list of amicable numbers, A063990.
First differs from A180163 at a(9). - Omar E. Pol, Oct 25 2017
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LINKS
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Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from T. D. Noe)
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FORMULA
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a(n) = A259180(2n-1) * A259180(2n). - Omar E. Pol, Oct 22 2017
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EXAMPLE
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a(9) = A002025(9) * A002046(9) = 63020 * 76084 = 4794813680.
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MATHEMATICA
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s[n_] := DivisorSigma[1, n]-n; smallAmicableQ[n_] := Module[{b=s[n]}, n<b && s[b]==n]; a=Select[Range[10^6], smallAmicableQ]; Table[n*s[n], {n, a}]
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CROSSREFS
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Cf. A002025, A002046, A180163, A259180.
Sequence in context: A242620 A203046 A180163 * A031659 A257150 A257157
Adjacent sequences: A180199 A180200 A180201 * A180203 A180204 A180205
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KEYWORD
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nonn
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AUTHOR
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T. D. Noe, Aug 15 2010
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STATUS
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approved
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