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A180202 The product of the two numbers in an amicable pair, A002025(n) * A002046(n). 4
62480, 1432640, 7660880, 27931280, 39685376, 116636864, 179299575, 318523136, 4794813680, 4483640576, 4773473775, 6100571295, 7076217500, 12475715175, 17094480975, 15069863936, 21699524864, 24011966300, 30304399616 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
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
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from T. D. Noe)
FORMULA
a(n) = A259180(2n-1) * A259180(2n). - Omar E. Pol, Oct 22 2017
EXAMPLE
a(9) = A002025(9) * A002046(9) = 63020 * 76084 = 4794813680.
MATHEMATICA
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}]
CROSSREFS
Sequence in context: A242620 A203046 A180163 * A031659 A257150 A257157
KEYWORD
nonn
AUTHOR
T. D. Noe, Aug 15 2010
STATUS
approved

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Last modified March 29 02:16 EDT 2024. Contains 371264 sequences. (Running on oeis4.)